Api/v1/accounts (#8)

* start work on accounts module

* plodding away on the accounts endpoint

* groundwork for other account routes

* add password validator

* validation utils

* require account approval flags

* comments

* comments

* go fmt

* comments

* add distributor stub

* rename api to federator

* tidy a bit

* validate new account requests

* rename r router

* comments

* add domain blocks

* add some more shortcuts

* add some more shortcuts

* check email + username availability

* email block checking for signups

* chunking away at it

* tick off a few more things

* some fiddling with tests

* add mock package

* relocate repo

* move mocks around

* set app id on new signups

* initialize oauth server properly

* rename oauth server

* proper mocking tests

* go fmt ./...

* add required fields

* change name of func

* move validation to account.go

* more tests!

* add some file utility tools

* add mediaconfig

* new shortcut

* add some more fields

* add followrequest model

* add notify

* update mastotypes

* mock out storage interface

* start building media interface

* start on update credentials

* mess about with media a bit more

* test image manipulation

* media more or less working

* account update nearly working

* rearranging my package ;) ;) ;)

* phew big stuff!!!!

* fix type checking

* *fiddles*

* Add CreateTables func

* account registration flow working

* tidy

* script to step through auth flow

* add a lil helper for generating user uris

* fiddling with federation a bit

* update progress

* Tidying and linting

21 files changed, 2525 insertions, 0 deletions

diff --git a/internal/apimodule/account/account.go b/internal/apimodule/account/account.go
new file mode 100644
index 000000000..2d9ddbb72
--- /dev/null
+++ b/internal/apimodule/account/account.go
@@ -0,0 +1,100 @@
+/*
+   GoToSocial
+   Copyright (C) 2021 GoToSocial Authors admin@gotosocial.org
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU Affero General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU Affero General Public License for more details.
+
+   You should have received a copy of the GNU Affero General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+package account
+
+import (
+	"fmt"
+	"net/http"
+	"strings"
+
+	"github.com/gin-gonic/gin"
+	"github.com/sirupsen/logrus"
+	"github.com/superseriousbusiness/gotosocial/internal/apimodule"
+	"github.com/superseriousbusiness/gotosocial/internal/config"
+	"github.com/superseriousbusiness/gotosocial/internal/db"
+	"github.com/superseriousbusiness/gotosocial/internal/db/model"
+	"github.com/superseriousbusiness/gotosocial/internal/media"
+	"github.com/superseriousbusiness/gotosocial/internal/oauth"
+	"github.com/superseriousbusiness/gotosocial/internal/router"
+)
+
+const (
+	idKey                 = "id"
+	basePath              = "/api/v1/accounts"
+	basePathWithID        = basePath + "/:" + idKey
+	verifyPath            = basePath + "/verify_credentials"
+	updateCredentialsPath = basePath + "/update_credentials"
+)
+
+type accountModule struct {
+	config       *config.Config
+	db           db.DB
+	oauthServer  oauth.Server
+	mediaHandler media.MediaHandler
+	log          *logrus.Logger
+}
+
+// New returns a new account module
+func New(config *config.Config, db db.DB, oauthServer oauth.Server, mediaHandler media.MediaHandler, log *logrus.Logger) apimodule.ClientAPIModule {
+	return &accountModule{
+		config:       config,
+		db:           db,
+		oauthServer:  oauthServer,
+		mediaHandler: mediaHandler,
+		log:          log,
+	}
+}
+
+// Route attaches all routes from this module to the given router
+func (m *accountModule) Route(r router.Router) error {
+	r.AttachHandler(http.MethodPost, basePath, m.accountCreatePOSTHandler)
+	r.AttachHandler(http.MethodGet, basePathWithID, m.muxHandler)
+	return nil
+}
+
+func (m *accountModule) CreateTables(db db.DB) error {
+	models := []interface{}{
+		&model.User{},
+		&model.Account{},
+		&model.Follow{},
+		&model.FollowRequest{},
+		&model.Status{},
+		&model.Application{},
+		&model.EmailDomainBlock{},
+		&model.MediaAttachment{},
+	}
+
+	for _, m := range models {
+		if err := db.CreateTable(m); err != nil {
+			return fmt.Errorf("error creating table: %s", err)
+		}
+	}
+	return nil
+}
+
+func (m *accountModule) muxHandler(c *gin.Context) {
+	ru := c.Request.RequestURI
+	if strings.HasPrefix(ru, verifyPath) {
+		m.accountVerifyGETHandler(c)
+	} else if strings.HasPrefix(ru, updateCredentialsPath) {
+		m.accountUpdateCredentialsPATCHHandler(c)
+	} else {
+		m.accountGETHandler(c)
+	}
+}
diff --git a/internal/apimodule/account/accountcreate.go b/internal/apimodule/account/accountcreate.go
new file mode 100644
index 000000000..58b98c0e4
--- /dev/null
+++ b/internal/apimodule/account/accountcreate.go
@@ -0,0 +1,155 @@
+/*
+   GoToSocial
+   Copyright (C) 2021 GoToSocial Authors admin@gotosocial.org
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU Affero General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU Affero General Public License for more details.
+
+   You should have received a copy of the GNU Affero General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+package account
+
+import (
+	"errors"
+	"fmt"
+	"net"
+	"net/http"
+
+	"github.com/gin-gonic/gin"
+	"github.com/superseriousbusiness/gotosocial/internal/config"
+	"github.com/superseriousbusiness/gotosocial/internal/db"
+	"github.com/superseriousbusiness/gotosocial/internal/db/model"
+	"github.com/superseriousbusiness/gotosocial/internal/oauth"
+	"github.com/superseriousbusiness/gotosocial/internal/util"
+	"github.com/superseriousbusiness/gotosocial/pkg/mastotypes"
+	"github.com/superseriousbusiness/oauth2/v4"
+)
+
+// accountCreatePOSTHandler handles create account requests, validates them,
+// and puts them in the database if they're valid.
+// It should be served as a POST at /api/v1/accounts
+func (m *accountModule) accountCreatePOSTHandler(c *gin.Context) {
+	l := m.log.WithField("func", "accountCreatePOSTHandler")
+	authed, err := oauth.MustAuth(c, true, true, false, false)
+	if err != nil {
+		l.Debugf("couldn't auth: %s", err)
+		c.JSON(http.StatusForbidden, gin.H{"error": err.Error()})
+		return
+	}
+
+	l.Trace("parsing request form")
+	form := &mastotypes.AccountCreateRequest{}
+	if err := c.ShouldBind(form); err != nil || form == nil {
+		l.Debugf("could not parse form from request: %s", err)
+		c.JSON(http.StatusBadRequest, gin.H{"error": "missing one or more required form values"})
+		return
+	}
+
+	l.Tracef("validating form %+v", form)
+	if err := validateCreateAccount(form, m.config.AccountsConfig, m.db); err != nil {
+		l.Debugf("error validating form: %s", err)
+		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
+		return
+	}
+
+	clientIP := c.ClientIP()
+	l.Tracef("attempting to parse client ip address %s", clientIP)
+	signUpIP := net.ParseIP(clientIP)
+	if signUpIP == nil {
+		l.Debugf("error validating sign up ip address %s", clientIP)
+		c.JSON(http.StatusBadRequest, gin.H{"error": "ip address could not be parsed from request"})
+		return
+	}
+
+	ti, err := m.accountCreate(form, signUpIP, authed.Token, authed.Application)
+	if err != nil {
+		l.Errorf("internal server error while creating new account: %s", err)
+		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+		return
+	}
+
+	c.JSON(http.StatusOK, ti)
+}
+
+// accountCreate does the dirty work of making an account and user in the database.
+// It then returns a token to the caller, for use with the new account, as per the
+// spec here: https://docs.joinmastodon.org/methods/accounts/
+func (m *accountModule) accountCreate(form *mastotypes.AccountCreateRequest, signUpIP net.IP, token oauth2.TokenInfo, app *model.Application) (*mastotypes.Token, error) {
+	l := m.log.WithField("func", "accountCreate")
+
+	// don't store a reason if we don't require one
+	reason := form.Reason
+	if !m.config.AccountsConfig.ReasonRequired {
+		reason = ""
+	}
+
+	l.Trace("creating new username and account")
+	user, err := m.db.NewSignup(form.Username, reason, m.config.AccountsConfig.RequireApproval, form.Email, form.Password, signUpIP, form.Locale, app.ID)
+	if err != nil {
+		return nil, fmt.Errorf("error creating new signup in the database: %s", err)
+	}
+
+	l.Tracef("generating a token for user %s with account %s and application %s", user.ID, user.AccountID, app.ID)
+	accessToken, err := m.oauthServer.GenerateUserAccessToken(token, app.ClientSecret, user.ID)
+	if err != nil {
+		return nil, fmt.Errorf("error creating new access token for user %s: %s", user.ID, err)
+	}
+
+	return &mastotypes.Token{
+		AccessToken: accessToken.GetAccess(),
+		TokenType:   "Bearer",
+		Scope:       accessToken.GetScope(),
+		CreatedAt:   accessToken.GetAccessCreateAt().Unix(),
+	}, nil
+}
+
+// validateCreateAccount checks through all the necessary prerequisites for creating a new account,
+// according to the provided account create request. If the account isn't eligible, an error will be returned.
+func validateCreateAccount(form *mastotypes.AccountCreateRequest, c *config.AccountsConfig, database db.DB) error {
+	if !c.OpenRegistration {
+		return errors.New("registration is not open for this server")
+	}
+
+	if err := util.ValidateUsername(form.Username); err != nil {
+		return err
+	}
+
+	if err := util.ValidateEmail(form.Email); err != nil {
+		return err
+	}
+
+	if err := util.ValidateNewPassword(form.Password); err != nil {
+		return err
+	}
+
+	if !form.Agreement {
+		return errors.New("agreement to terms and conditions not given")
+	}
+
+	if err := util.ValidateLanguage(form.Locale); err != nil {
+		return err
+	}
+
+	if err := util.ValidateSignUpReason(form.Reason, c.ReasonRequired); err != nil {
+		return err
+	}
+
+	if err := database.IsEmailAvailable(form.Email); err != nil {
+		return err
+	}
+
+	if err := database.IsUsernameAvailable(form.Username); err != nil {
+		return err
+	}
+
+	return nil
+}
diff --git a/internal/apimodule/account/accountcreate_test.go b/internal/apimodule/account/accountcreate_test.go
new file mode 100644
index 000000000..d14ae3852
--- /dev/null
+++ b/internal/apimodule/account/accountcreate_test.go
@@ -0,0 +1,545 @@
+/*
+   GoToSocial
+   Copyright (C) 2021 GoToSocial Authors admin@gotosocial.org
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU Affero General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU Affero General Public License for more details.
+
+   You should have received a copy of the GNU Affero General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+package account
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"mime/multipart"
+	"net/http"
+	"net/http/httptest"
+	"net/url"
+	"os"
+	"testing"
+	"time"
+
+	"github.com/gin-gonic/gin"
+	"github.com/google/uuid"
+	"github.com/sirupsen/logrus"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/mock"
+	"github.com/stretchr/testify/suite"
+	"github.com/superseriousbusiness/gotosocial/internal/config"
+	"github.com/superseriousbusiness/gotosocial/internal/db"
+	"github.com/superseriousbusiness/gotosocial/internal/db/model"
+	"github.com/superseriousbusiness/gotosocial/internal/media"
+	"github.com/superseriousbusiness/gotosocial/internal/oauth"
+	"github.com/superseriousbusiness/gotosocial/internal/storage"
+	"github.com/superseriousbusiness/gotosocial/pkg/mastotypes"
+	"github.com/superseriousbusiness/oauth2/v4"
+	"github.com/superseriousbusiness/oauth2/v4/models"
+	oauthmodels "github.com/superseriousbusiness/oauth2/v4/models"
+	"golang.org/x/crypto/bcrypt"
+)
+
+type AccountCreateTestSuite struct {
+	suite.Suite
+	config               *config.Config
+	log                  *logrus.Logger
+	testAccountLocal     *model.Account
+	testApplication      *model.Application
+	testToken            oauth2.TokenInfo
+	mockOauthServer      *oauth.MockServer
+	mockStorage          *storage.MockStorage
+	mediaHandler         media.MediaHandler
+	db                   db.DB
+	accountModule        *accountModule
+	newUserFormHappyPath url.Values
+}
+
+/*
+	TEST INFRASTRUCTURE
+*/
+
+// SetupSuite sets some variables on the suite that we can use as consts (more or less) throughout
+func (suite *AccountCreateTestSuite) SetupSuite() {
+	// some of our subsequent entities need a log so create this here
+	log := logrus.New()
+	log.SetLevel(logrus.TraceLevel)
+	suite.log = log
+
+	suite.testAccountLocal = &model.Account{
+		ID:       uuid.NewString(),
+		Username: "test_user",
+	}
+
+	// can use this test application throughout
+	suite.testApplication = &model.Application{
+		ID:           "weeweeeeeeeeeeeeee",
+		Name:         "a test application",
+		Website:      "https://some-application-website.com",
+		RedirectURI:  "http://localhost:8080",
+		ClientID:     "a-known-client-id",
+		ClientSecret: "some-secret",
+		Scopes:       "read",
+		VapidKey:     "aaaaaa-aaaaaaaa-aaaaaaaaaaa",
+	}
+
+	// can use this test token throughout
+	suite.testToken = &oauthmodels.Token{
+		ClientID:      "a-known-client-id",
+		RedirectURI:   "http://localhost:8080",
+		Scope:         "read",
+		Code:          "123456789",
+		CodeCreateAt:  time.Now(),
+		CodeExpiresIn: time.Duration(10 * time.Minute),
+	}
+
+	// Direct config to local postgres instance
+	c := config.Empty()
+	c.Protocol = "http"
+	c.Host = "localhost"
+	c.DBConfig = &config.DBConfig{
+		Type:            "postgres",
+		Address:         "localhost",
+		Port:            5432,
+		User:            "postgres",
+		Password:        "postgres",
+		Database:        "postgres",
+		ApplicationName: "gotosocial",
+	}
+	c.MediaConfig = &config.MediaConfig{
+		MaxImageSize: 2 << 20,
+	}
+	c.StorageConfig = &config.StorageConfig{
+		Backend:       "local",
+		BasePath:      "/tmp",
+		ServeProtocol: "http",
+		ServeHost:     "localhost",
+		ServeBasePath: "/fileserver/media",
+	}
+	suite.config = c
+
+	// use an actual database for this, because it's just easier than mocking one out
+	database, err := db.New(context.Background(), c, log)
+	if err != nil {
+		suite.FailNow(err.Error())
+	}
+	suite.db = database
+
+	// we need to mock the oauth server because account creation needs it to create a new token
+	suite.mockOauthServer = &oauth.MockServer{}
+	suite.mockOauthServer.On("GenerateUserAccessToken", suite.testToken, suite.testApplication.ClientSecret, mock.AnythingOfType("string")).Run(func(args mock.Arguments) {
+		l := suite.log.WithField("func", "GenerateUserAccessToken")
+		token := args.Get(0).(oauth2.TokenInfo)
+		l.Infof("received token %+v", token)
+		clientSecret := args.Get(1).(string)
+		l.Infof("received clientSecret %+v", clientSecret)
+		userID := args.Get(2).(string)
+		l.Infof("received userID %+v", userID)
+	}).Return(&models.Token{
+		Code: "we're authorized now!",
+	}, nil)
+
+	suite.mockStorage = &storage.MockStorage{}
+	// We don't need storage to do anything for these tests, so just simulate a success and do nothing -- we won't need to return anything from storage
+	suite.mockStorage.On("StoreFileAt", mock.AnythingOfType("string"), mock.AnythingOfType("[]uint8")).Return(nil)
+
+	// set a media handler because some handlers (eg update credentials) need to upload media (new header/avatar)
+	suite.mediaHandler = media.New(suite.config, suite.db, suite.mockStorage, log)
+
+	// and finally here's the thing we're actually testing!
+	suite.accountModule = New(suite.config, suite.db, suite.mockOauthServer, suite.mediaHandler, suite.log).(*accountModule)
+}
+
+func (suite *AccountCreateTestSuite) TearDownSuite() {
+	if err := suite.db.Stop(context.Background()); err != nil {
+		logrus.Panicf("error closing db connection: %s", err)
+	}
+}
+
+// SetupTest creates a db connection and creates necessary tables before each test
+func (suite *AccountCreateTestSuite) SetupTest() {
+	// create all the tables we might need in thie suite
+	models := []interface{}{
+		&model.User{},
+		&model.Account{},
+		&model.Follow{},
+		&model.FollowRequest{},
+		&model.Status{},
+		&model.Application{},
+		&model.EmailDomainBlock{},
+		&model.MediaAttachment{},
+	}
+	for _, m := range models {
+		if err := suite.db.CreateTable(m); err != nil {
+			logrus.Panicf("db connection error: %s", err)
+		}
+	}
+
+	// form to submit for happy path account create requests -- this will be changed inside tests so it's better to set it before each test
+	suite.newUserFormHappyPath = url.Values{
+		"reason":    []string{"a very good reason that's at least 40 characters i swear"},
+		"username":  []string{"test_user"},
+		"email":     []string{"user@example.org"},
+		"password":  []string{"very-strong-password"},
+		"agreement": []string{"true"},
+		"locale":    []string{"en"},
+	}
+
+	// same with accounts config
+	suite.config.AccountsConfig = &config.AccountsConfig{
+		OpenRegistration: true,
+		RequireApproval:  true,
+		ReasonRequired:   true,
+	}
+}
+
+// TearDownTest drops tables to make sure there's no data in the db
+func (suite *AccountCreateTestSuite) TearDownTest() {
+
+	// remove all the tables we might have used so it's clear for the next test
+	models := []interface{}{
+		&model.User{},
+		&model.Account{},
+		&model.Follow{},
+		&model.FollowRequest{},
+		&model.Status{},
+		&model.Application{},
+		&model.EmailDomainBlock{},
+		&model.MediaAttachment{},
+	}
+	for _, m := range models {
+		if err := suite.db.DropTable(m); err != nil {
+			logrus.Panicf("error dropping table: %s", err)
+		}
+	}
+}
+
+/*
+	ACTUAL TESTS
+*/
+
+/*
+	TESTING: AccountCreatePOSTHandler
+*/
+
+// TestAccountCreatePOSTHandlerSuccessful checks the happy path for an account creation request: all the fields provided are valid,
+// and at the end of it a new user and account should be added into the database.
+//
+// This is the handler served at /api/v1/accounts as POST
+func (suite *AccountCreateTestSuite) TestAccountCreatePOSTHandlerSuccessful() {
+
+	// setup
+	recorder := httptest.NewRecorder()
+	ctx, _ := gin.CreateTestContext(recorder)
+	ctx.Set(oauth.SessionAuthorizedApplication, suite.testApplication)
+	ctx.Set(oauth.SessionAuthorizedToken, suite.testToken)
+	ctx.Request = httptest.NewRequest(http.MethodPost, fmt.Sprintf("http://localhost:8080/%s", basePath), nil) // the endpoint we're hitting
+	ctx.Request.Form = suite.newUserFormHappyPath
+	suite.accountModule.accountCreatePOSTHandler(ctx)
+
+	// check response
+
+	// 1. we should have OK from our call to the function
+	suite.EqualValues(http.StatusOK, recorder.Code)
+
+	// 2. we should have a token in the result body
+	result := recorder.Result()
+	defer result.Body.Close()
+	b, err := ioutil.ReadAll(result.Body)
+	assert.NoError(suite.T(), err)
+	t := &mastotypes.Token{}
+	err = json.Unmarshal(b, t)
+	assert.NoError(suite.T(), err)
+	assert.Equal(suite.T(), "we're authorized now!", t.AccessToken)
+
+	// check new account
+
+	// 1. we should be able to get the new account from the db
+	acct := &model.Account{}
+	err = suite.db.GetWhere("username", "test_user", acct)
+	assert.NoError(suite.T(), err)
+	assert.NotNil(suite.T(), acct)
+	// 2. reason should be set
+	assert.Equal(suite.T(), suite.newUserFormHappyPath.Get("reason"), acct.Reason)
+	// 3. display name should be equal to username by default
+	assert.Equal(suite.T(), suite.newUserFormHappyPath.Get("username"), acct.DisplayName)
+	// 4. domain should be nil because this is a local account
+	assert.Nil(suite.T(), nil, acct.Domain)
+	// 5. id should be set and parseable as a uuid
+	assert.NotNil(suite.T(), acct.ID)
+	_, err = uuid.Parse(acct.ID)
+	assert.Nil(suite.T(), err)
+	// 6. private and public key should be set
+	assert.NotNil(suite.T(), acct.PrivateKey)
+	assert.NotNil(suite.T(), acct.PublicKey)
+
+	// check new user
+
+	// 1. we should be able to get the new user from the db
+	usr := &model.User{}
+	err = suite.db.GetWhere("unconfirmed_email", suite.newUserFormHappyPath.Get("email"), usr)
+	assert.Nil(suite.T(), err)
+	assert.NotNil(suite.T(), usr)
+
+	// 2. user should have account id set to account we got above
+	assert.Equal(suite.T(), acct.ID, usr.AccountID)
+
+	// 3. id should be set and parseable as a uuid
+	assert.NotNil(suite.T(), usr.ID)
+	_, err = uuid.Parse(usr.ID)
+	assert.Nil(suite.T(), err)
+
+	// 4. locale should be equal to what we requested
+	assert.Equal(suite.T(), suite.newUserFormHappyPath.Get("locale"), usr.Locale)
+
+	// 5. created by application id should be equal to the app id
+	assert.Equal(suite.T(), suite.testApplication.ID, usr.CreatedByApplicationID)
+
+	// 6. password should be matcheable to what we set above
+	err = bcrypt.CompareHashAndPassword([]byte(usr.EncryptedPassword), []byte(suite.newUserFormHappyPath.Get("password")))
+	assert.Nil(suite.T(), err)
+}
+
+// TestAccountCreatePOSTHandlerNoAuth makes sure that the handler fails when no authorization is provided:
+// only registered applications can create accounts, and we don't provide one here.
+func (suite *AccountCreateTestSuite) TestAccountCreatePOSTHandlerNoAuth() {
+
+	// setup
+	recorder := httptest.NewRecorder()
+	ctx, _ := gin.CreateTestContext(recorder)
+	ctx.Request = httptest.NewRequest(http.MethodPost, fmt.Sprintf("http://localhost:8080/%s", basePath), nil) // the endpoint we're hitting
+	ctx.Request.Form = suite.newUserFormHappyPath
+	suite.accountModule.accountCreatePOSTHandler(ctx)
+
+	// check response
+
+	// 1. we should have forbidden from our call to the function because we didn't auth
+	suite.EqualValues(http.StatusForbidden, recorder.Code)
+
+	// 2. we should have an error message in the result body
+	result := recorder.Result()
+	defer result.Body.Close()
+	b, err := ioutil.ReadAll(result.Body)
+	assert.NoError(suite.T(), err)
+	assert.Equal(suite.T(), `{"error":"not authorized"}`, string(b))
+}
+
+// TestAccountCreatePOSTHandlerNoAuth makes sure that the handler fails when no form is provided at all.
+func (suite *AccountCreateTestSuite) TestAccountCreatePOSTHandlerNoForm() {
+
+	// setup
+	recorder := httptest.NewRecorder()
+	ctx, _ := gin.CreateTestContext(recorder)
+	ctx.Set(oauth.SessionAuthorizedApplication, suite.testApplication)
+	ctx.Set(oauth.SessionAuthorizedToken, suite.testToken)
+	ctx.Request = httptest.NewRequest(http.MethodPost, fmt.Sprintf("http://localhost:8080/%s", basePath), nil) // the endpoint we're hitting
+	suite.accountModule.accountCreatePOSTHandler(ctx)
+
+	// check response
+	suite.EqualValues(http.StatusBadRequest, recorder.Code)
+
+	// 2. we should have an error message in the result body
+	result := recorder.Result()
+	defer result.Body.Close()
+	b, err := ioutil.ReadAll(result.Body)
+	assert.NoError(suite.T(), err)
+	assert.Equal(suite.T(), `{"error":"missing one or more required form values"}`, string(b))
+}
+
+// TestAccountCreatePOSTHandlerWeakPassword makes sure that the handler fails when a weak password is provided
+func (suite *AccountCreateTestSuite) TestAccountCreatePOSTHandlerWeakPassword() {
+
+	// setup
+	recorder := httptest.NewRecorder()
+	ctx, _ := gin.CreateTestContext(recorder)
+	ctx.Set(oauth.SessionAuthorizedApplication, suite.testApplication)
+	ctx.Set(oauth.SessionAuthorizedToken, suite.testToken)
+	ctx.Request = httptest.NewRequest(http.MethodPost, fmt.Sprintf("http://localhost:8080/%s", basePath), nil) // the endpoint we're hitting
+	ctx.Request.Form = suite.newUserFormHappyPath
+	// set a weak password
+	ctx.Request.Form.Set("password", "weak")
+	suite.accountModule.accountCreatePOSTHandler(ctx)
+
+	// check response
+	suite.EqualValues(http.StatusBadRequest, recorder.Code)
+
+	// 2. we should have an error message in the result body
+	result := recorder.Result()
+	defer result.Body.Close()
+	b, err := ioutil.ReadAll(result.Body)
+	assert.NoError(suite.T(), err)
+	assert.Equal(suite.T(), `{"error":"insecure password, try including more special characters, using uppercase letters, using numbers or using a longer password"}`, string(b))
+}
+
+// TestAccountCreatePOSTHandlerWeirdLocale makes sure that the handler fails when a weird locale is provided
+func (suite *AccountCreateTestSuite) TestAccountCreatePOSTHandlerWeirdLocale() {
+
+	// setup
+	recorder := httptest.NewRecorder()
+	ctx, _ := gin.CreateTestContext(recorder)
+	ctx.Set(oauth.SessionAuthorizedApplication, suite.testApplication)
+	ctx.Set(oauth.SessionAuthorizedToken, suite.testToken)
+	ctx.Request = httptest.NewRequest(http.MethodPost, fmt.Sprintf("http://localhost:8080/%s", basePath), nil) // the endpoint we're hitting
+	ctx.Request.Form = suite.newUserFormHappyPath
+	// set an invalid locale
+	ctx.Request.Form.Set("locale", "neverneverland")
+	suite.accountModule.accountCreatePOSTHandler(ctx)
+
+	// check response
+	suite.EqualValues(http.StatusBadRequest, recorder.Code)
+
+	// 2. we should have an error message in the result body
+	result := recorder.Result()
+	defer result.Body.Close()
+	b, err := ioutil.ReadAll(result.Body)
+	assert.NoError(suite.T(), err)
+	assert.Equal(suite.T(), `{"error":"language: tag is not well-formed"}`, string(b))
+}
+
+// TestAccountCreatePOSTHandlerRegistrationsClosed makes sure that the handler fails when registrations are closed
+func (suite *AccountCreateTestSuite) TestAccountCreatePOSTHandlerRegistrationsClosed() {
+
+	// setup
+	recorder := httptest.NewRecorder()
+	ctx, _ := gin.CreateTestContext(recorder)
+	ctx.Set(oauth.SessionAuthorizedApplication, suite.testApplication)
+	ctx.Set(oauth.SessionAuthorizedToken, suite.testToken)
+	ctx.Request = httptest.NewRequest(http.MethodPost, fmt.Sprintf("http://localhost:8080/%s", basePath), nil) // the endpoint we're hitting
+	ctx.Request.Form = suite.newUserFormHappyPath
+
+	// close registrations
+	suite.config.AccountsConfig.OpenRegistration = false
+	suite.accountModule.accountCreatePOSTHandler(ctx)
+
+	// check response
+	suite.EqualValues(http.StatusBadRequest, recorder.Code)
+
+	// 2. we should have an error message in the result body
+	result := recorder.Result()
+	defer result.Body.Close()
+	b, err := ioutil.ReadAll(result.Body)
+	assert.NoError(suite.T(), err)
+	assert.Equal(suite.T(), `{"error":"registration is not open for this server"}`, string(b))
+}
+
+// TestAccountCreatePOSTHandlerReasonNotProvided makes sure that the handler fails when no reason is provided but one is required
+func (suite *AccountCreateTestSuite) TestAccountCreatePOSTHandlerReasonNotProvided() {
+
+	// setup
+	recorder := httptest.NewRecorder()
+	ctx, _ := gin.CreateTestContext(recorder)
+	ctx.Set(oauth.SessionAuthorizedApplication, suite.testApplication)
+	ctx.Set(oauth.SessionAuthorizedToken, suite.testToken)
+	ctx.Request = httptest.NewRequest(http.MethodPost, fmt.Sprintf("http://localhost:8080/%s", basePath), nil) // the endpoint we're hitting
+	ctx.Request.Form = suite.newUserFormHappyPath
+
+	// remove reason
+	ctx.Request.Form.Set("reason", "")
+
+	suite.accountModule.accountCreatePOSTHandler(ctx)
+
+	// check response
+	suite.EqualValues(http.StatusBadRequest, recorder.Code)
+
+	// 2. we should have an error message in the result body
+	result := recorder.Result()
+	defer result.Body.Close()
+	b, err := ioutil.ReadAll(result.Body)
+	assert.NoError(suite.T(), err)
+	assert.Equal(suite.T(), `{"error":"no reason provided"}`, string(b))
+}
+
+// TestAccountCreatePOSTHandlerReasonNotProvided makes sure that the handler fails when a crappy reason is presented but a good one is required
+func (suite *AccountCreateTestSuite) TestAccountCreatePOSTHandlerInsufficientReason() {
+
+	// setup
+	recorder := httptest.NewRecorder()
+	ctx, _ := gin.CreateTestContext(recorder)
+	ctx.Set(oauth.SessionAuthorizedApplication, suite.testApplication)
+	ctx.Set(oauth.SessionAuthorizedToken, suite.testToken)
+	ctx.Request = httptest.NewRequest(http.MethodPost, fmt.Sprintf("http://localhost:8080/%s", basePath), nil) // the endpoint we're hitting
+	ctx.Request.Form = suite.newUserFormHappyPath
+
+	// remove reason
+	ctx.Request.Form.Set("reason", "just cuz")
+
+	suite.accountModule.accountCreatePOSTHandler(ctx)
+
+	// check response
+	suite.EqualValues(http.StatusBadRequest, recorder.Code)
+
+	// 2. we should have an error message in the result body
+	result := recorder.Result()
+	defer result.Body.Close()
+	b, err := ioutil.ReadAll(result.Body)
+	assert.NoError(suite.T(), err)
+	assert.Equal(suite.T(), `{"error":"reason should be at least 40 chars but 'just cuz' was 8"}`, string(b))
+}
+
+/*
+	TESTING: AccountUpdateCredentialsPATCHHandler
+*/
+
+func (suite *AccountCreateTestSuite) TestAccountUpdateCredentialsPATCHHandler() {
+
+	// put test local account in db
+	err := suite.db.Put(suite.testAccountLocal)
+	assert.NoError(suite.T(), err)
+
+	// attach avatar to request
+	aviFile, err := os.Open("../../media/test/test-jpeg.jpg")
+	assert.NoError(suite.T(), err)
+	body := &bytes.Buffer{}
+	writer := multipart.NewWriter(body)
+
+	part, err := writer.CreateFormFile("avatar", "test-jpeg.jpg")
+	assert.NoError(suite.T(), err)
+
+	_, err = io.Copy(part, aviFile)
+	assert.NoError(suite.T(), err)
+
+	err = aviFile.Close()
+	assert.NoError(suite.T(), err)
+
+	err = writer.Close()
+	assert.NoError(suite.T(), err)
+
+	// setup
+	recorder := httptest.NewRecorder()
+	ctx, _ := gin.CreateTestContext(recorder)
+	ctx.Set(oauth.SessionAuthorizedAccount, suite.testAccountLocal)
+	ctx.Set(oauth.SessionAuthorizedToken, suite.testToken)
+	ctx.Request = httptest.NewRequest(http.MethodPatch, fmt.Sprintf("http://localhost:8080/%s", updateCredentialsPath), body) // the endpoint we're hitting
+	ctx.Request.Header.Set("Content-Type", writer.FormDataContentType())
+	suite.accountModule.accountUpdateCredentialsPATCHHandler(ctx)
+
+	// check response
+
+	// 1. we should have OK because our request was valid
+	suite.EqualValues(http.StatusOK, recorder.Code)
+
+	// 2. we should have an error message in the result body
+	result := recorder.Result()
+	defer result.Body.Close()
+	// TODO: implement proper checks here
+	//
+	// b, err := ioutil.ReadAll(result.Body)
+	// assert.NoError(suite.T(), err)
+	// assert.Equal(suite.T(), `{"error":"not authorized"}`, string(b))
+}
+
+func TestAccountCreateTestSuite(t *testing.T) {
+	suite.Run(t, new(AccountCreateTestSuite))
+}
diff --git a/internal/apimodule/account/accountget.go b/internal/apimodule/account/accountget.go
new file mode 100644
index 000000000..5ee93386d
--- /dev/null
+++ b/internal/apimodule/account/accountget.go
@@ -0,0 +1,57 @@
+/*
+   GoToSocial
+   Copyright (C) 2021 GoToSocial Authors admin@gotosocial.org
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU Affero General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU Affero General Public License for more details.
+
+   You should have received a copy of the GNU Affero General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+package account
+
+import (
+	"net/http"
+
+	"github.com/gin-gonic/gin"
+	"github.com/superseriousbusiness/gotosocial/internal/db"
+	"github.com/superseriousbusiness/gotosocial/internal/db/model"
+)
+
+// accountGetHandler serves the account information held by the server in response to a GET
+// request. It should be served as a GET at /api/v1/accounts/:id.
+//
+// See: https://docs.joinmastodon.org/methods/accounts/
+func (m *accountModule) accountGETHandler(c *gin.Context) {
+	targetAcctID := c.Param(idKey)
+	if targetAcctID == "" {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "no account id specified"})
+		return
+	}
+
+	targetAccount := &model.Account{}
+	if err := m.db.GetByID(targetAcctID, targetAccount); err != nil {
+		if _, ok := err.(db.ErrNoEntries); ok {
+			c.JSON(http.StatusNotFound, gin.H{"error": "Record not found"})
+			return
+		}
+		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+		return
+	}
+
+	acctInfo, err := m.db.AccountToMastoPublic(targetAccount)
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+		return
+	}
+
+	c.JSON(http.StatusOK, acctInfo)
+}
diff --git a/internal/apimodule/account/accountupdate.go b/internal/apimodule/account/accountupdate.go
new file mode 100644
index 000000000..6686d3a50
--- /dev/null
+++ b/internal/apimodule/account/accountupdate.go
@@ -0,0 +1,259 @@
+/*
+   GoToSocial
+   Copyright (C) 2021 GoToSocial Authors admin@gotosocial.org
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU Affero General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU Affero General Public License for more details.
+
+   You should have received a copy of the GNU Affero General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+package account
+
+import (
+	"bytes"
+	"errors"
+	"fmt"
+	"io"
+	"mime/multipart"
+	"net/http"
+
+	"github.com/gin-gonic/gin"
+	"github.com/superseriousbusiness/gotosocial/internal/db/model"
+	"github.com/superseriousbusiness/gotosocial/internal/oauth"
+	"github.com/superseriousbusiness/gotosocial/internal/util"
+	"github.com/superseriousbusiness/gotosocial/pkg/mastotypes"
+)
+
+// accountUpdateCredentialsPATCHHandler allows a user to modify their account/profile settings.
+// It should be served as a PATCH at /api/v1/accounts/update_credentials
+//
+// TODO: this can be optimized massively by building up a picture of what we want the new account
+// details to be, and then inserting it all in the database at once. As it is, we do queries one-by-one
+// which is not gonna make the database very happy when lots of requests are going through.
+// This way it would also be safer because the update won't happen until *all* the fields are validated.
+// Otherwise we risk doing a partial update and that's gonna cause probllleeemmmsss.
+func (m *accountModule) accountUpdateCredentialsPATCHHandler(c *gin.Context) {
+	l := m.log.WithField("func", "accountUpdateCredentialsPATCHHandler")
+	authed, err := oauth.MustAuth(c, true, false, false, true)
+	if err != nil {
+		l.Debugf("couldn't auth: %s", err)
+		c.JSON(http.StatusForbidden, gin.H{"error": err.Error()})
+		return
+	}
+	l.Tracef("retrieved account %+v", authed.Account.ID)
+
+	l.Trace("parsing request form")
+	form := &mastotypes.UpdateCredentialsRequest{}
+	if err := c.ShouldBind(form); err != nil || form == nil {
+		l.Debugf("could not parse form from request: %s", err)
+		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
+		return
+	}
+
+	// if everything on the form is nil, then nothing has been set and we shouldn't continue
+	if form.Discoverable == nil && form.Bot == nil && form.DisplayName == nil && form.Note == nil && form.Avatar == nil && form.Header == nil && form.Locked == nil && form.Source == nil && form.FieldsAttributes == nil {
+		l.Debugf("could not parse form from request")
+		c.JSON(http.StatusBadRequest, gin.H{"error": "empty form submitted"})
+		return
+	}
+
+	if form.Discoverable != nil {
+		if err := m.db.UpdateOneByID(authed.Account.ID, "discoverable", *form.Discoverable, &model.Account{}); err != nil {
+			l.Debugf("error updating discoverable: %s", err)
+			c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+			return
+		}
+	}
+
+	if form.Bot != nil {
+		if err := m.db.UpdateOneByID(authed.Account.ID, "bot", *form.Bot, &model.Account{}); err != nil {
+			l.Debugf("error updating bot: %s", err)
+			c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+			return
+		}
+	}
+
+	if form.DisplayName != nil {
+		if err := util.ValidateDisplayName(*form.DisplayName); err != nil {
+			c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
+			return
+		}
+		if err := m.db.UpdateOneByID(authed.Account.ID, "display_name", *form.DisplayName, &model.Account{}); err != nil {
+			c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+			return
+		}
+	}
+
+	if form.Note != nil {
+		if err := util.ValidateNote(*form.Note); err != nil {
+			c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
+			return
+		}
+		if err := m.db.UpdateOneByID(authed.Account.ID, "note", *form.Note, &model.Account{}); err != nil {
+			l.Debugf("error updating note: %s", err)
+			c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+			return
+		}
+	}
+
+	if form.Avatar != nil && form.Avatar.Size != 0 {
+		avatarInfo, err := m.UpdateAccountAvatar(form.Avatar, authed.Account.ID)
+		if err != nil {
+			l.Debugf("could not update avatar for account %s: %s", authed.Account.ID, err)
+			c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
+			return
+		}
+		l.Tracef("new avatar info for account %s is %+v", authed.Account.ID, avatarInfo)
+	}
+
+	if form.Header != nil && form.Header.Size != 0 {
+		headerInfo, err := m.UpdateAccountHeader(form.Header, authed.Account.ID)
+		if err != nil {
+			l.Debugf("could not update header for account %s: %s", authed.Account.ID, err)
+			c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
+			return
+		}
+		l.Tracef("new header info for account %s is %+v", authed.Account.ID, headerInfo)
+	}
+
+	if form.Locked != nil {
+		if err := m.db.UpdateOneByID(authed.Account.ID, "locked", *form.Locked, &model.Account{}); err != nil {
+			c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+			return
+		}
+	}
+
+	if form.Source != nil {
+		if form.Source.Language != nil {
+			if err := util.ValidateLanguage(*form.Source.Language); err != nil {
+				c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
+				return
+			}
+			if err := m.db.UpdateOneByID(authed.Account.ID, "language", *form.Source.Language, &model.Account{}); err != nil {
+				c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+				return
+			}
+		}
+
+		if form.Source.Sensitive != nil {
+			if err := m.db.UpdateOneByID(authed.Account.ID, "locked", *form.Locked, &model.Account{}); err != nil {
+				c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+				return
+			}
+		}
+
+		if form.Source.Privacy != nil {
+			if err := util.ValidatePrivacy(*form.Source.Privacy); err != nil {
+				c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
+				return
+			}
+			if err := m.db.UpdateOneByID(authed.Account.ID, "privacy", *form.Source.Privacy, &model.Account{}); err != nil {
+				c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+				return
+			}
+		}
+	}
+
+	// if form.FieldsAttributes != nil {
+	// 	// TODO: parse fields attributes nicely and update
+	// }
+
+	// fetch the account with all updated values set
+	updatedAccount := &model.Account{}
+	if err := m.db.GetByID(authed.Account.ID, updatedAccount); err != nil {
+		l.Debugf("could not fetch updated account %s: %s", authed.Account.ID, err)
+		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+		return
+	}
+
+	acctSensitive, err := m.db.AccountToMastoSensitive(updatedAccount)
+	if err != nil {
+		l.Tracef("could not convert account into mastosensitive account: %s", err)
+		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+		return
+	}
+
+	l.Tracef("conversion successful, returning OK and mastosensitive account %+v", acctSensitive)
+	c.JSON(http.StatusOK, acctSensitive)
+}
+
+/*
+	HELPER FUNCTIONS
+*/
+
+// TODO: try to combine the below two functions because this is a lot of code repetition.
+
+// UpdateAccountAvatar does the dirty work of checking the avatar part of an account update form,
+// parsing and checking the image, and doing the necessary updates in the database for this to become
+// the account's new avatar image.
+func (m *accountModule) UpdateAccountAvatar(avatar *multipart.FileHeader, accountID string) (*model.MediaAttachment, error) {
+	var err error
+	if int(avatar.Size) > m.config.MediaConfig.MaxImageSize {
+		err = fmt.Errorf("avatar with size %d exceeded max image size of %d bytes", avatar.Size, m.config.MediaConfig.MaxImageSize)
+		return nil, err
+	}
+	f, err := avatar.Open()
+	if err != nil {
+		return nil, fmt.Errorf("could not read provided avatar: %s", err)
+	}
+
+	// extract the bytes
+	buf := new(bytes.Buffer)
+	size, err := io.Copy(buf, f)
+	if err != nil {
+		return nil, fmt.Errorf("could not read provided avatar: %s", err)
+	}
+	if size == 0 {
+		return nil, errors.New("could not read provided avatar: size 0 bytes")
+	}
+
+	// do the setting
+	avatarInfo, err := m.mediaHandler.SetHeaderOrAvatarForAccountID(buf.Bytes(), accountID, "avatar")
+	if err != nil {
+		return nil, fmt.Errorf("error processing avatar: %s", err)
+	}
+
+	return avatarInfo, f.Close()
+}
+
+// UpdateAccountHeader does the dirty work of checking the header part of an account update form,
+// parsing and checking the image, and doing the necessary updates in the database for this to become
+// the account's new header image.
+func (m *accountModule) UpdateAccountHeader(header *multipart.FileHeader, accountID string) (*model.MediaAttachment, error) {
+	var err error
+	if int(header.Size) > m.config.MediaConfig.MaxImageSize {
+		err = fmt.Errorf("header with size %d exceeded max image size of %d bytes", header.Size, m.config.MediaConfig.MaxImageSize)
+		return nil, err
+	}
+	f, err := header.Open()
+	if err != nil {
+		return nil, fmt.Errorf("could not read provided header: %s", err)
+	}
+
+	// extract the bytes
+	buf := new(bytes.Buffer)
+	size, err := io.Copy(buf, f)
+	if err != nil {
+		return nil, fmt.Errorf("could not read provided header: %s", err)
+	}
+	if size == 0 {
+		return nil, errors.New("could not read provided header: size 0 bytes")
+	}
+
+	// do the setting
+	headerInfo, err := m.mediaHandler.SetHeaderOrAvatarForAccountID(buf.Bytes(), accountID, "header")
+	if err != nil {
+		return nil, fmt.Errorf("error processing header: %s", err)
+	}
+
+	return headerInfo, f.Close()
+}
diff --git a/internal/apimodule/account/accountupdate_test.go b/internal/apimodule/account/accountupdate_test.go
new file mode 100644
index 000000000..651b4d29d
--- /dev/null
+++ b/internal/apimodule/account/accountupdate_test.go
@@ -0,0 +1,298 @@
+/*
+   GoToSocial
+   Copyright (C) 2021 GoToSocial Authors admin@gotosocial.org
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU Affero General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU Affero General Public License for more details.
+
+   You should have received a copy of the GNU Affero General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+package account
+
+import (
+	"bytes"
+	"context"
+	"fmt"
+	"io"
+	"mime/multipart"
+	"net/http"
+	"net/http/httptest"
+	"net/url"
+	"os"
+	"testing"
+	"time"
+
+	"github.com/gin-gonic/gin"
+	"github.com/google/uuid"
+	"github.com/sirupsen/logrus"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/mock"
+	"github.com/stretchr/testify/suite"
+	"github.com/superseriousbusiness/gotosocial/internal/config"
+	"github.com/superseriousbusiness/gotosocial/internal/db"
+	"github.com/superseriousbusiness/gotosocial/internal/db/model"
+	"github.com/superseriousbusiness/gotosocial/internal/media"
+	"github.com/superseriousbusiness/gotosocial/internal/oauth"
+	"github.com/superseriousbusiness/gotosocial/internal/storage"
+	"github.com/superseriousbusiness/oauth2/v4"
+	"github.com/superseriousbusiness/oauth2/v4/models"
+	oauthmodels "github.com/superseriousbusiness/oauth2/v4/models"
+)
+
+type AccountUpdateTestSuite struct {
+	suite.Suite
+	config               *config.Config
+	log                  *logrus.Logger
+	testAccountLocal     *model.Account
+	testApplication      *model.Application
+	testToken            oauth2.TokenInfo
+	mockOauthServer      *oauth.MockServer
+	mockStorage          *storage.MockStorage
+	mediaHandler         media.MediaHandler
+	db                   db.DB
+	accountModule        *accountModule
+	newUserFormHappyPath url.Values
+}
+
+/*
+	TEST INFRASTRUCTURE
+*/
+
+// SetupSuite sets some variables on the suite that we can use as consts (more or less) throughout
+func (suite *AccountUpdateTestSuite) SetupSuite() {
+	// some of our subsequent entities need a log so create this here
+	log := logrus.New()
+	log.SetLevel(logrus.TraceLevel)
+	suite.log = log
+
+	suite.testAccountLocal = &model.Account{
+		ID:       uuid.NewString(),
+		Username: "test_user",
+	}
+
+	// can use this test application throughout
+	suite.testApplication = &model.Application{
+		ID:           "weeweeeeeeeeeeeeee",
+		Name:         "a test application",
+		Website:      "https://some-application-website.com",
+		RedirectURI:  "http://localhost:8080",
+		ClientID:     "a-known-client-id",
+		ClientSecret: "some-secret",
+		Scopes:       "read",
+		VapidKey:     "aaaaaa-aaaaaaaa-aaaaaaaaaaa",
+	}
+
+	// can use this test token throughout
+	suite.testToken = &oauthmodels.Token{
+		ClientID:      "a-known-client-id",
+		RedirectURI:   "http://localhost:8080",
+		Scope:         "read",
+		Code:          "123456789",
+		CodeCreateAt:  time.Now(),
+		CodeExpiresIn: time.Duration(10 * time.Minute),
+	}
+
+	// Direct config to local postgres instance
+	c := config.Empty()
+	c.Protocol = "http"
+	c.Host = "localhost"
+	c.DBConfig = &config.DBConfig{
+		Type:            "postgres",
+		Address:         "localhost",
+		Port:            5432,
+		User:            "postgres",
+		Password:        "postgres",
+		Database:        "postgres",
+		ApplicationName: "gotosocial",
+	}
+	c.MediaConfig = &config.MediaConfig{
+		MaxImageSize: 2 << 20,
+	}
+	c.StorageConfig = &config.StorageConfig{
+		Backend:       "local",
+		BasePath:      "/tmp",
+		ServeProtocol: "http",
+		ServeHost:     "localhost",
+		ServeBasePath: "/fileserver/media",
+	}
+	suite.config = c
+
+	// use an actual database for this, because it's just easier than mocking one out
+	database, err := db.New(context.Background(), c, log)
+	if err != nil {
+		suite.FailNow(err.Error())
+	}
+	suite.db = database
+
+	// we need to mock the oauth server because account creation needs it to create a new token
+	suite.mockOauthServer = &oauth.MockServer{}
+	suite.mockOauthServer.On("GenerateUserAccessToken", suite.testToken, suite.testApplication.ClientSecret, mock.AnythingOfType("string")).Run(func(args mock.Arguments) {
+		l := suite.log.WithField("func", "GenerateUserAccessToken")
+		token := args.Get(0).(oauth2.TokenInfo)
+		l.Infof("received token %+v", token)
+		clientSecret := args.Get(1).(string)
+		l.Infof("received clientSecret %+v", clientSecret)
+		userID := args.Get(2).(string)
+		l.Infof("received userID %+v", userID)
+	}).Return(&models.Token{
+		Code: "we're authorized now!",
+	}, nil)
+
+	suite.mockStorage = &storage.MockStorage{}
+	// We don't need storage to do anything for these tests, so just simulate a success and do nothing -- we won't need to return anything from storage
+	suite.mockStorage.On("StoreFileAt", mock.AnythingOfType("string"), mock.AnythingOfType("[]uint8")).Return(nil)
+
+	// set a media handler because some handlers (eg update credentials) need to upload media (new header/avatar)
+	suite.mediaHandler = media.New(suite.config, suite.db, suite.mockStorage, log)
+
+	// and finally here's the thing we're actually testing!
+	suite.accountModule = New(suite.config, suite.db, suite.mockOauthServer, suite.mediaHandler, suite.log).(*accountModule)
+}
+
+func (suite *AccountUpdateTestSuite) TearDownSuite() {
+	if err := suite.db.Stop(context.Background()); err != nil {
+		logrus.Panicf("error closing db connection: %s", err)
+	}
+}
+
+// SetupTest creates a db connection and creates necessary tables before each test
+func (suite *AccountUpdateTestSuite) SetupTest() {
+	// create all the tables we might need in thie suite
+	models := []interface{}{
+		&model.User{},
+		&model.Account{},
+		&model.Follow{},
+		&model.FollowRequest{},
+		&model.Status{},
+		&model.Application{},
+		&model.EmailDomainBlock{},
+		&model.MediaAttachment{},
+	}
+	for _, m := range models {
+		if err := suite.db.CreateTable(m); err != nil {
+			logrus.Panicf("db connection error: %s", err)
+		}
+	}
+
+	// form to submit for happy path account create requests -- this will be changed inside tests so it's better to set it before each test
+	suite.newUserFormHappyPath = url.Values{
+		"reason":    []string{"a very good reason that's at least 40 characters i swear"},
+		"username":  []string{"test_user"},
+		"email":     []string{"user@example.org"},
+		"password":  []string{"very-strong-password"},
+		"agreement": []string{"true"},
+		"locale":    []string{"en"},
+	}
+
+	// same with accounts config
+	suite.config.AccountsConfig = &config.AccountsConfig{
+		OpenRegistration: true,
+		RequireApproval:  true,
+		ReasonRequired:   true,
+	}
+}
+
+// TearDownTest drops tables to make sure there's no data in the db
+func (suite *AccountUpdateTestSuite) TearDownTest() {
+
+	// remove all the tables we might have used so it's clear for the next test
+	models := []interface{}{
+		&model.User{},
+		&model.Account{},
+		&model.Follow{},
+		&model.FollowRequest{},
+		&model.Status{},
+		&model.Application{},
+		&model.EmailDomainBlock{},
+		&model.MediaAttachment{},
+	}
+	for _, m := range models {
+		if err := suite.db.DropTable(m); err != nil {
+			logrus.Panicf("error dropping table: %s", err)
+		}
+	}
+}
+
+/*
+	ACTUAL TESTS
+*/
+
+/*
+	TESTING: AccountUpdateCredentialsPATCHHandler
+*/
+
+func (suite *AccountUpdateTestSuite) TestAccountUpdateCredentialsPATCHHandler() {
+
+	// put test local account in db
+	err := suite.db.Put(suite.testAccountLocal)
+	assert.NoError(suite.T(), err)
+
+	// attach avatar to request form
+	avatarFile, err := os.Open("../../media/test/test-jpeg.jpg")
+	assert.NoError(suite.T(), err)
+	body := &bytes.Buffer{}
+	writer := multipart.NewWriter(body)
+
+	avatarPart, err := writer.CreateFormFile("avatar", "test-jpeg.jpg")
+	assert.NoError(suite.T(), err)
+
+	_, err = io.Copy(avatarPart, avatarFile)
+	assert.NoError(suite.T(), err)
+
+	err = avatarFile.Close()
+	assert.NoError(suite.T(), err)
+
+	// set display name to a new value
+	displayNamePart, err := writer.CreateFormField("display_name")
+	assert.NoError(suite.T(), err)
+
+	_, err = io.Copy(displayNamePart, bytes.NewBufferString("test_user_wohoah"))
+	assert.NoError(suite.T(), err)
+
+	// set locked to true
+	lockedPart, err := writer.CreateFormField("locked")
+	assert.NoError(suite.T(), err)
+
+	_, err = io.Copy(lockedPart, bytes.NewBufferString("true"))
+	assert.NoError(suite.T(), err)
+
+	// close the request writer, the form is now prepared
+	err = writer.Close()
+	assert.NoError(suite.T(), err)
+
+	// setup
+	recorder := httptest.NewRecorder()
+	ctx, _ := gin.CreateTestContext(recorder)
+	ctx.Set(oauth.SessionAuthorizedAccount, suite.testAccountLocal)
+	ctx.Set(oauth.SessionAuthorizedToken, suite.testToken)
+	ctx.Request = httptest.NewRequest(http.MethodPatch, fmt.Sprintf("http://localhost:8080/%s", updateCredentialsPath), body) // the endpoint we're hitting
+	ctx.Request.Header.Set("Content-Type", writer.FormDataContentType())
+	suite.accountModule.accountUpdateCredentialsPATCHHandler(ctx)
+
+	// check response
+
+	// 1. we should have OK because our request was valid
+	suite.EqualValues(http.StatusOK, recorder.Code)
+
+	// 2. we should have an error message in the result body
+	result := recorder.Result()
+	defer result.Body.Close()
+	// TODO: implement proper checks here
+	//
+	// b, err := ioutil.ReadAll(result.Body)
+	// assert.NoError(suite.T(), err)
+	// assert.Equal(suite.T(), `{"error":"not authorized"}`, string(b))
+}
+
+func TestAccountUpdateTestSuite(t *testing.T) {
+	suite.Run(t, new(AccountUpdateTestSuite))
+}
diff --git a/internal/apimodule/account/accountverify.go b/internal/apimodule/account/accountverify.go
new file mode 100644
index 000000000..fe8d24b22
--- /dev/null
+++ b/internal/apimodule/account/accountverify.go
@@ -0,0 +1,50 @@
+/*
+   GoToSocial
+   Copyright (C) 2021 GoToSocial Authors admin@gotosocial.org
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU Affero General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU Affero General Public License for more details.
+
+   You should have received a copy of the GNU Affero General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+package account
+
+import (
+	"net/http"
+
+	"github.com/gin-gonic/gin"
+	"github.com/superseriousbusiness/gotosocial/internal/oauth"
+)
+
+// accountVerifyGETHandler serves a user's account details to them IF they reached this
+// handler while in possession of a valid token, according to the oauth middleware.
+// It should be served as a GET at /api/v1/accounts/verify_credentials
+func (m *accountModule) accountVerifyGETHandler(c *gin.Context) {
+	l := m.log.WithField("func", "accountVerifyGETHandler")
+	authed, err := oauth.MustAuth(c, true, false, false, true)
+	if err != nil {
+		l.Debugf("couldn't auth: %s", err)
+		c.JSON(http.StatusForbidden, gin.H{"error": err.Error()})
+		return
+	}
+
+	l.Tracef("retrieved account %+v, converting to mastosensitive...", authed.Account.ID)
+	acctSensitive, err := m.db.AccountToMastoSensitive(authed.Account)
+	if err != nil {
+		l.Tracef("could not convert account into mastosensitive account: %s", err)
+		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+		return
+	}
+
+	l.Tracef("conversion successful, returning OK and mastosensitive account %+v", acctSensitive)
+	c.JSON(http.StatusOK, acctSensitive)
+}
diff --git a/internal/apimodule/account/accountverify_test.go b/internal/apimodule/account/accountverify_test.go
new file mode 100644
index 000000000..223a0c145
--- /dev/null
+++ b/internal/apimodule/account/accountverify_test.go
@@ -0,0 +1,19 @@
+/*
+   GoToSocial
+   Copyright (C) 2021 GoToSocial Authors admin@gotosocial.org
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU Affero General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU Affero General Public License for more details.
+
+   You should have received a copy of the GNU Affero General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+package account
diff --git a/internal/apimodule/apimodule.go b/internal/apimodule/apimodule.go
new file mode 100644
index 000000000..52275c6df
--- /dev/null
+++ b/internal/apimodule/apimodule.go
@@ -0,0 +1,33 @@
+/*
+   GoToSocial
+   Copyright (C) 2021 GoToSocial Authors admin@gotosocial.org
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU Affero General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU Affero General Public License for more details.
+
+   You should have received a copy of the GNU Affero General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+// Package apimodule is basically a wrapper for a lot of modules (in subdirectories) that satisfy the ClientAPIModule interface.
+package apimodule
+
+import (
+	"github.com/superseriousbusiness/gotosocial/internal/db"
+	"github.com/superseriousbusiness/gotosocial/internal/router"
+)
+
+// ClientAPIModule represents a chunk of code (usually contained in a single package) that adds a set
+// of functionalities and side effects to a router, by mapping routes and handlers onto it--in other words, a REST API ;)
+// A ClientAPIMpdule corresponds roughly to one main path of the gotosocial REST api, for example /api/v1/accounts/ or /oauth/
+type ClientAPIModule interface {
+	Route(s router.Router) error
+	CreateTables(db db.DB) error
+}
diff --git a/internal/apimodule/app/app.go b/internal/apimodule/app/app.go
new file mode 100644
index 000000000..534f4cd3e
--- /dev/null
+++ b/internal/apimodule/app/app.go
@@ -0,0 +1,71 @@
+/*
+   GoToSocial
+   Copyright (C) 2021 GoToSocial Authors admin@gotosocial.org
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU Affero General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU Affero General Public License for more details.
+
+   You should have received a copy of the GNU Affero General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+package app
+
+import (
+	"fmt"
+	"net/http"
+
+	"github.com/sirupsen/logrus"
+	"github.com/superseriousbusiness/gotosocial/internal/apimodule"
+	"github.com/superseriousbusiness/gotosocial/internal/db"
+	"github.com/superseriousbusiness/gotosocial/internal/db/model"
+	"github.com/superseriousbusiness/gotosocial/internal/oauth"
+	"github.com/superseriousbusiness/gotosocial/internal/router"
+)
+
+const appsPath = "/api/v1/apps"
+
+type appModule struct {
+	server oauth.Server
+	db     db.DB
+	log    *logrus.Logger
+}
+
+// New returns a new auth module
+func New(srv oauth.Server, db db.DB, log *logrus.Logger) apimodule.ClientAPIModule {
+	return &appModule{
+		server: srv,
+		db:     db,
+		log:    log,
+	}
+}
+
+// Route satisfies the RESTAPIModule interface
+func (m *appModule) Route(s router.Router) error {
+	s.AttachHandler(http.MethodPost, appsPath, m.appsPOSTHandler)
+	return nil
+}
+
+func (m *appModule) CreateTables(db db.DB) error {
+	models := []interface{}{
+		&oauth.Client{},
+		&oauth.Token{},
+		&model.User{},
+		&model.Account{},
+		&model.Application{},
+	}
+
+	for _, m := range models {
+		if err := db.CreateTable(m); err != nil {
+			return fmt.Errorf("error creating table: %s", err)
+		}
+	}
+	return nil
+}
diff --git a/internal/apimodule/app/app_test.go b/internal/apimodule/app/app_test.go
new file mode 100644
index 000000000..d45b04e74
--- /dev/null
+++ b/internal/apimodule/app/app_test.go
@@ -0,0 +1,21 @@
+/*
+   GoToSocial
+   Copyright (C) 2021 GoToSocial Authors admin@gotosocial.org
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU Affero General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU Affero General Public License for more details.
+
+   You should have received a copy of the GNU Affero General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+package app
+
+// TODO: write tests
diff --git a/internal/apimodule/app/appcreate.go b/internal/apimodule/app/appcreate.go
new file mode 100644
index 000000000..cd5aff701
--- /dev/null
+++ b/internal/apimodule/app/appcreate.go
@@ -0,0 +1,113 @@
+/*
+   GoToSocial
+   Copyright (C) 2021 GoToSocial Authors admin@gotosocial.org
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU Affero General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU Affero General Public License for more details.
+
+   You should have received a copy of the GNU Affero General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+package app
+
+import (
+	"fmt"
+	"net/http"
+
+	"github.com/gin-gonic/gin"
+	"github.com/google/uuid"
+	"github.com/superseriousbusiness/gotosocial/internal/db/model"
+	"github.com/superseriousbusiness/gotosocial/internal/oauth"
+	"github.com/superseriousbusiness/gotosocial/pkg/mastotypes"
+)
+
+// appsPOSTHandler should be served at https://example.org/api/v1/apps
+// It is equivalent to: https://docs.joinmastodon.org/methods/apps/
+func (m *appModule) appsPOSTHandler(c *gin.Context) {
+	l := m.log.WithField("func", "AppsPOSTHandler")
+	l.Trace("entering AppsPOSTHandler")
+
+	form := &mastotypes.ApplicationPOSTRequest{}
+	if err := c.ShouldBind(form); err != nil {
+		c.JSON(http.StatusUnprocessableEntity, gin.H{"error": err.Error()})
+		return
+	}
+
+	// permitted length for most fields
+	permittedLength := 64
+	// redirect can be a bit bigger because we probably need to encode data in the redirect uri
+	permittedRedirect := 256
+
+	// check lengths of fields before proceeding so the user can't spam huge entries into the database
+	if len(form.ClientName) > permittedLength {
+		c.JSON(http.StatusBadRequest, gin.H{"error": fmt.Sprintf("client_name must be less than %d bytes", permittedLength)})
+		return
+	}
+	if len(form.Website) > permittedLength {
+		c.JSON(http.StatusBadRequest, gin.H{"error": fmt.Sprintf("website must be less than %d bytes", permittedLength)})
+		return
+	}
+	if len(form.RedirectURIs) > permittedRedirect {
+		c.JSON(http.StatusBadRequest, gin.H{"error": fmt.Sprintf("redirect_uris must be less than %d bytes", permittedRedirect)})
+		return
+	}
+	if len(form.Scopes) > permittedLength {
+		c.JSON(http.StatusBadRequest, gin.H{"error": fmt.Sprintf("scopes must be less than %d bytes", permittedLength)})
+		return
+	}
+
+	// set default 'read' for scopes if it's not set, this follows the default of the mastodon api https://docs.joinmastodon.org/methods/apps/
+	var scopes string
+	if form.Scopes == "" {
+		scopes = "read"
+	} else {
+		scopes = form.Scopes
+	}
+
+	// generate new IDs for this application and its associated client
+	clientID := uuid.NewString()
+	clientSecret := uuid.NewString()
+	vapidKey := uuid.NewString()
+
+	// generate the application to put in the database
+	app := &model.Application{
+		Name:         form.ClientName,
+		Website:      form.Website,
+		RedirectURI:  form.RedirectURIs,
+		ClientID:     clientID,
+		ClientSecret: clientSecret,
+		Scopes:       scopes,
+		VapidKey:     vapidKey,
+	}
+
+	// chuck it in the db
+	if err := m.db.Put(app); err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+		return
+	}
+
+	// now we need to model an oauth client from the application that the oauth library can use
+	oc := &oauth.Client{
+		ID:     clientID,
+		Secret: clientSecret,
+		Domain: form.RedirectURIs,
+		UserID: "", // This client isn't yet associated with a specific user,  it's just an app client right now
+	}
+
+	// chuck it in the db
+	if err := m.db.Put(oc); err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+		return
+	}
+
+	// done, return the new app information per the spec here: https://docs.joinmastodon.org/methods/apps/
+	c.JSON(http.StatusOK, app.ToMasto())
+}
diff --git a/internal/apimodule/auth/README.md b/internal/apimodule/auth/README.md
new file mode 100644
index 000000000..96b2443c1
--- /dev/null
+++ b/internal/apimodule/auth/README.md
@@ -0,0 +1,5 @@
+# auth
+
+This package provides uses the [GoToSocial oauth2](https://github.com/gotosocial/oauth2) module (forked from [go-oauth2](https://github.com/go-oauth2/oauth2)) to provide [oauth2](https://www.oauth.com/) functionality to the GoToSocial client API.
+
+It also provides a handler/middleware for attaching to the Gin engine for validating authenticated users.
diff --git a/internal/apimodule/auth/auth.go b/internal/apimodule/auth/auth.go
new file mode 100644
index 000000000..3a85a4364
--- /dev/null
+++ b/internal/apimodule/auth/auth.go
@@ -0,0 +1,89 @@
+/*
+   GoToSocial
+   Copyright (C) 2021 GoToSocial Authors admin@gotosocial.org
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU Affero General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU Affero General Public License for more details.
+
+   You should have received a copy of the GNU Affero General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+// Package auth is a module that provides oauth functionality to a router.
+// It adds the following paths:
+//    /auth/sign_in
+//    /oauth/token
+//    /oauth/authorize
+// It also includes the oauthTokenMiddleware, which can be attached to a router to authenticate every request by Bearer token.
+package auth
+
+import (
+	"fmt"
+	"net/http"
+
+	"github.com/sirupsen/logrus"
+	"github.com/superseriousbusiness/gotosocial/internal/apimodule"
+	"github.com/superseriousbusiness/gotosocial/internal/db"
+	"github.com/superseriousbusiness/gotosocial/internal/db/model"
+	"github.com/superseriousbusiness/gotosocial/internal/oauth"
+	"github.com/superseriousbusiness/gotosocial/internal/router"
+)
+
+const (
+	authSignInPath     = "/auth/sign_in"
+	oauthTokenPath     = "/oauth/token"
+	oauthAuthorizePath = "/oauth/authorize"
+)
+
+type authModule struct {
+	server oauth.Server
+	db     db.DB
+	log    *logrus.Logger
+}
+
+// New returns a new auth module
+func New(srv oauth.Server, db db.DB, log *logrus.Logger) apimodule.ClientAPIModule {
+	return &authModule{
+		server: srv,
+		db:     db,
+		log:    log,
+	}
+}
+
+// Route satisfies the RESTAPIModule interface
+func (m *authModule) Route(s router.Router) error {
+	s.AttachHandler(http.MethodGet, authSignInPath, m.signInGETHandler)
+	s.AttachHandler(http.MethodPost, authSignInPath, m.signInPOSTHandler)
+
+	s.AttachHandler(http.MethodPost, oauthTokenPath, m.tokenPOSTHandler)
+
+	s.AttachHandler(http.MethodGet, oauthAuthorizePath, m.authorizeGETHandler)
+	s.AttachHandler(http.MethodPost, oauthAuthorizePath, m.authorizePOSTHandler)
+
+	s.AttachMiddleware(m.oauthTokenMiddleware)
+	return nil
+}
+
+func (m *authModule) CreateTables(db db.DB) error {
+	models := []interface{}{
+		&oauth.Client{},
+		&oauth.Token{},
+		&model.User{},
+		&model.Account{},
+		&model.Application{},
+	}
+
+	for _, m := range models {
+		if err := db.CreateTable(m); err != nil {
+			return fmt.Errorf("error creating table: %s", err)
+		}
+	}
+	return nil
+}
diff --git a/internal/apimodule/auth/auth_test.go b/internal/apimodule/auth/auth_test.go
new file mode 100644
index 000000000..0ec9b4a41
--- /dev/null
+++ b/internal/apimodule/auth/auth_test.go
@@ -0,0 +1,189 @@
+/*
+   GoToSocial
+   Copyright (C) 2021 GoToSocial Authors admin@gotosocial.org
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU Affero General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU Affero General Public License for more details.
+
+   You should have received a copy of the GNU Affero General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+package auth
+
+import (
+	"context"
+	"fmt"
+	"testing"
+	"time"
+
+	"github.com/google/uuid"
+	"github.com/sirupsen/logrus"
+	"github.com/stretchr/testify/suite"
+	"github.com/superseriousbusiness/gotosocial/internal/config"
+	"github.com/superseriousbusiness/gotosocial/internal/db"
+	"github.com/superseriousbusiness/gotosocial/internal/db/model"
+	"github.com/superseriousbusiness/gotosocial/internal/oauth"
+	"github.com/superseriousbusiness/gotosocial/internal/router"
+	"golang.org/x/crypto/bcrypt"
+)
+
+type AuthTestSuite struct {
+	suite.Suite
+	oauthServer     oauth.Server
+	db              db.DB
+	testAccount     *model.Account
+	testApplication *model.Application
+	testUser        *model.User
+	testClient      *oauth.Client
+	config          *config.Config
+}
+
+// SetupSuite sets some variables on the suite that we can use as consts (more or less) throughout
+func (suite *AuthTestSuite) SetupSuite() {
+	c := config.Empty()
+	// we're running on localhost without https so set the protocol to http
+	c.Protocol = "http"
+	// just for testing
+	c.Host = "localhost:8080"
+	// because go tests are run within the test package directory, we need to fiddle with the templateconfig
+	// basedir in a way that we wouldn't normally have to do when running the binary, in order to make
+	// the templates actually load
+	c.TemplateConfig.BaseDir = "../../../web/template/"
+	c.DBConfig = &config.DBConfig{
+		Type:            "postgres",
+		Address:         "localhost",
+		Port:            5432,
+		User:            "postgres",
+		Password:        "postgres",
+		Database:        "postgres",
+		ApplicationName: "gotosocial",
+	}
+	suite.config = c
+
+	encryptedPassword, err := bcrypt.GenerateFromPassword([]byte("password"), bcrypt.DefaultCost)
+	if err != nil {
+		logrus.Panicf("error encrypting user pass: %s", err)
+	}
+
+	acctID := uuid.NewString()
+
+	suite.testAccount = &model.Account{
+		ID:       acctID,
+		Username: "test_user",
+	}
+	suite.testUser = &model.User{
+		EncryptedPassword: string(encryptedPassword),
+		Email:             "user@example.org",
+		AccountID:         acctID,
+	}
+	suite.testClient = &oauth.Client{
+		ID:     "a-known-client-id",
+		Secret: "some-secret",
+		Domain: fmt.Sprintf("%s://%s", c.Protocol, c.Host),
+	}
+	suite.testApplication = &model.Application{
+		Name:         "a test application",
+		Website:      "https://some-application-website.com",
+		RedirectURI:  "http://localhost:8080",
+		ClientID:     "a-known-client-id",
+		ClientSecret: "some-secret",
+		Scopes:       "read",
+		VapidKey:     uuid.NewString(),
+	}
+}
+
+// SetupTest creates a postgres connection and creates the oauth_clients table before each test
+func (suite *AuthTestSuite) SetupTest() {
+
+	log := logrus.New()
+	log.SetLevel(logrus.TraceLevel)
+	db, err := db.New(context.Background(), suite.config, log)
+	if err != nil {
+		logrus.Panicf("error creating database connection: %s", err)
+	}
+
+	suite.db = db
+
+	models := []interface{}{
+		&oauth.Client{},
+		&oauth.Token{},
+		&model.User{},
+		&model.Account{},
+		&model.Application{},
+	}
+
+	for _, m := range models {
+		if err := suite.db.CreateTable(m); err != nil {
+			logrus.Panicf("db connection error: %s", err)
+		}
+	}
+
+	suite.oauthServer = oauth.New(suite.db, log)
+
+	if err := suite.db.Put(suite.testAccount); err != nil {
+		logrus.Panicf("could not insert test account into db: %s", err)
+	}
+	if err := suite.db.Put(suite.testUser); err != nil {
+		logrus.Panicf("could not insert test user into db: %s", err)
+	}
+	if err := suite.db.Put(suite.testClient); err != nil {
+		logrus.Panicf("could not insert test client into db: %s", err)
+	}
+	if err := suite.db.Put(suite.testApplication); err != nil {
+		logrus.Panicf("could not insert test application into db: %s", err)
+	}
+
+}
+
+// TearDownTest drops the oauth_clients table and closes the pg connection after each test
+func (suite *AuthTestSuite) TearDownTest() {
+	models := []interface{}{
+		&oauth.Client{},
+		&oauth.Token{},
+		&model.User{},
+		&model.Account{},
+		&model.Application{},
+	}
+	for _, m := range models {
+		if err := suite.db.DropTable(m); err != nil {
+			logrus.Panicf("error dropping table: %s", err)
+		}
+	}
+	if err := suite.db.Stop(context.Background()); err != nil {
+		logrus.Panicf("error closing db connection: %s", err)
+	}
+	suite.db = nil
+}
+
+func (suite *AuthTestSuite) TestAPIInitialize() {
+	log := logrus.New()
+	log.SetLevel(logrus.TraceLevel)
+
+	r, err := router.New(suite.config, log)
+	if err != nil {
+		suite.FailNow(fmt.Sprintf("error mapping routes onto router: %s", err))
+	}
+
+	api := New(suite.oauthServer, suite.db, log)
+	if err := api.Route(r); err != nil {
+		suite.FailNow(fmt.Sprintf("error mapping routes onto router: %s", err))
+	}
+
+	r.Start()
+	time.Sleep(60 * time.Second)
+	if err := r.Stop(context.Background()); err != nil {
+		suite.FailNow(fmt.Sprintf("error stopping router: %s", err))
+	}
+}
+
+func TestAuthTestSuite(t *testing.T) {
+	suite.Run(t, new(AuthTestSuite))
+}
diff --git a/internal/apimodule/auth/authorize.go b/internal/apimodule/auth/authorize.go
new file mode 100644
index 000000000..4a27cc20e
--- /dev/null
+++ b/internal/apimodule/auth/authorize.go
@@ -0,0 +1,204 @@
+/*
+   GoToSocial
+   Copyright (C) 2021 GoToSocial Authors admin@gotosocial.org
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU Affero General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU Affero General Public License for more details.
+
+   You should have received a copy of the GNU Affero General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+package auth
+
+import (
+	"errors"
+	"fmt"
+	"net/http"
+	"net/url"
+
+	"github.com/gin-contrib/sessions"
+	"github.com/gin-gonic/gin"
+	"github.com/sirupsen/logrus"
+	"github.com/superseriousbusiness/gotosocial/internal/db/model"
+	"github.com/superseriousbusiness/gotosocial/pkg/mastotypes"
+)
+
+// authorizeGETHandler should be served as GET at https://example.org/oauth/authorize
+// The idea here is to present an oauth authorize page to the user, with a button
+// that they have to click to accept. See here: https://docs.joinmastodon.org/methods/apps/oauth/#authorize-a-user
+func (m *authModule) authorizeGETHandler(c *gin.Context) {
+	l := m.log.WithField("func", "AuthorizeGETHandler")
+	s := sessions.Default(c)
+
+	// UserID will be set in the session by AuthorizePOSTHandler if the caller has already gone through the authentication flow
+	// If it's not set, then we don't know yet who the user is, so we need to redirect them to the sign in page.
+	userID, ok := s.Get("userid").(string)
+	if !ok || userID == "" {
+		l.Trace("userid was empty, parsing form then redirecting to sign in page")
+		if err := parseAuthForm(c, l); err != nil {
+			c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
+		} else {
+			c.Redirect(http.StatusFound, authSignInPath)
+		}
+		return
+	}
+
+	// We can use the client_id on the session to retrieve info about the app associated with the client_id
+	clientID, ok := s.Get("client_id").(string)
+	if !ok || clientID == "" {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "no client_id found in session"})
+		return
+	}
+	app := &model.Application{
+		ClientID: clientID,
+	}
+	if err := m.db.GetWhere("client_id", app.ClientID, app); err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": fmt.Sprintf("no application found for client id %s", clientID)})
+		return
+	}
+
+	// we can also use the userid of the user to fetch their username from the db to greet them nicely <3
+	user := &model.User{
+		ID: userID,
+	}
+	if err := m.db.GetByID(user.ID, user); err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+		return
+	}
+
+	acct := &model.Account{
+		ID: user.AccountID,
+	}
+
+	if err := m.db.GetByID(acct.ID, acct); err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+		return
+	}
+
+	// Finally we should also get the redirect and scope of this particular request, as stored in the session.
+	redirect, ok := s.Get("redirect_uri").(string)
+	if !ok || redirect == "" {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "no redirect_uri found in session"})
+		return
+	}
+	scope, ok := s.Get("scope").(string)
+	if !ok || scope == "" {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "no scope found in session"})
+		return
+	}
+
+	// the authorize template will display a form to the user where they can get some information
+	// about the app that's trying to authorize, and the scope of the request.
+	// They can then approve it if it looks OK to them, which will POST to the AuthorizePOSTHandler
+	l.Trace("serving authorize html")
+	c.HTML(http.StatusOK, "authorize.tmpl", gin.H{
+		"appname":    app.Name,
+		"appwebsite": app.Website,
+		"redirect":   redirect,
+		"scope":      scope,
+		"user":       acct.Username,
+	})
+}
+
+// authorizePOSTHandler should be served as POST at https://example.org/oauth/authorize
+// At this point we assume that the user has A) logged in and B) accepted that the app should act for them,
+// so we should proceed with the authentication flow and generate an oauth token for them if we can.
+// See here: https://docs.joinmastodon.org/methods/apps/oauth/#authorize-a-user
+func (m *authModule) authorizePOSTHandler(c *gin.Context) {
+	l := m.log.WithField("func", "AuthorizePOSTHandler")
+	s := sessions.Default(c)
+
+	// At this point we know the user has said 'yes' to allowing the application and oauth client
+	// work for them, so we can set the
+
+	// We need to retrieve the original form submitted to the authorizeGEThandler, and
+	// recreate it on the request so that it can be used further by the oauth2 library.
+	// So first fetch all the values from the session.
+	forceLogin, ok := s.Get("force_login").(string)
+	if !ok {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "session missing force_login"})
+		return
+	}
+	responseType, ok := s.Get("response_type").(string)
+	if !ok || responseType == "" {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "session missing response_type"})
+		return
+	}
+	clientID, ok := s.Get("client_id").(string)
+	if !ok || clientID == "" {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "session missing client_id"})
+		return
+	}
+	redirectURI, ok := s.Get("redirect_uri").(string)
+	if !ok || redirectURI == "" {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "session missing redirect_uri"})
+		return
+	}
+	scope, ok := s.Get("scope").(string)
+	if !ok {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "session missing scope"})
+		return
+	}
+	userID, ok := s.Get("userid").(string)
+	if !ok {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "session missing userid"})
+		return
+	}
+	// we're done with the session so we can clear it now
+	s.Clear()
+
+	// now set the values on the request
+	values := url.Values{}
+	values.Set("force_login", forceLogin)
+	values.Set("response_type", responseType)
+	values.Set("client_id", clientID)
+	values.Set("redirect_uri", redirectURI)
+	values.Set("scope", scope)
+	values.Set("userid", userID)
+	c.Request.Form = values
+	l.Tracef("values on request set to %+v", c.Request.Form)
+
+	// and proceed with authorization using the oauth2 library
+	if err := m.server.HandleAuthorizeRequest(c.Writer, c.Request); err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
+	}
+}
+
+// parseAuthForm parses the OAuthAuthorize form in the gin context, and stores
+// the values in the form into the session.
+func parseAuthForm(c *gin.Context, l *logrus.Entry) error {
+	s := sessions.Default(c)
+
+	// first make sure they've filled out the authorize form with the required values
+	form := &mastotypes.OAuthAuthorize{}
+	if err := c.ShouldBind(form); err != nil {
+		return err
+	}
+	l.Tracef("parsed form: %+v", form)
+
+	// these fields are *required* so check 'em
+	if form.ResponseType == "" || form.ClientID == "" || form.RedirectURI == "" {
+		return errors.New("missing one of: response_type, client_id or redirect_uri")
+	}
+
+	// set default scope to read
+	if form.Scope == "" {
+		form.Scope = "read"
+	}
+
+	// save these values from the form so we can use them elsewhere in the session
+	s.Set("force_login", form.ForceLogin)
+	s.Set("response_type", form.ResponseType)
+	s.Set("client_id", form.ClientID)
+	s.Set("redirect_uri", form.RedirectURI)
+	s.Set("scope", form.Scope)
+	return s.Save()
+}
diff --git a/internal/apimodule/auth/middleware.go b/internal/apimodule/auth/middleware.go
new file mode 100644
index 000000000..32fc24d52
--- /dev/null
+++ b/internal/apimodule/auth/middleware.go
@@ -0,0 +1,76 @@
+/*
+   GoToSocial
+   Copyright (C) 2021 GoToSocial Authors admin@gotosocial.org
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU Affero General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU Affero General Public License for more details.
+
+   You should have received a copy of the GNU Affero General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+package auth
+
+import (
+	"github.com/gin-gonic/gin"
+	"github.com/superseriousbusiness/gotosocial/internal/db/model"
+	"github.com/superseriousbusiness/gotosocial/internal/oauth"
+)
+
+// oauthTokenMiddleware checks if the client has presented a valid oauth Bearer token.
+// If so, it will check the User that the token belongs to, and set that in the context of
+// the request. Then, it will look up the account for that user, and set that in the request too.
+// If user or account can't be found, then the handler won't *fail*, in case the server wants to allow
+// public requests that don't have a Bearer token set (eg., for public instance information and so on).
+func (m *authModule) oauthTokenMiddleware(c *gin.Context) {
+	l := m.log.WithField("func", "ValidatePassword")
+	l.Trace("entering OauthTokenMiddleware")
+
+	ti, err := m.server.ValidationBearerToken(c.Request)
+	if err != nil {
+		l.Trace("no valid token presented: continuing with unauthenticated request")
+		return
+	}
+	c.Set(oauth.SessionAuthorizedToken, ti)
+	l.Tracef("set gin context %s to %+v", oauth.SessionAuthorizedToken, ti)
+
+	// check for user-level token
+	if uid := ti.GetUserID(); uid != "" {
+		l.Tracef("authenticated user %s with bearer token, scope is %s", uid, ti.GetScope())
+
+		// fetch user's and account for this user id
+		user := &model.User{}
+		if err := m.db.GetByID(uid, user); err != nil || user == nil {
+			l.Warnf("no user found for validated uid %s", uid)
+			return
+		}
+		c.Set(oauth.SessionAuthorizedUser, user)
+		l.Tracef("set gin context %s to %+v", oauth.SessionAuthorizedUser, user)
+
+		acct := &model.Account{}
+		if err := m.db.GetByID(user.AccountID, acct); err != nil || acct == nil {
+			l.Warnf("no account found for validated user %s", uid)
+			return
+		}
+		c.Set(oauth.SessionAuthorizedAccount, acct)
+		l.Tracef("set gin context %s to %+v", oauth.SessionAuthorizedAccount, acct)
+	}
+
+	// check for application token
+	if cid := ti.GetClientID(); cid != "" {
+		l.Tracef("authenticated client %s with bearer token, scope is %s", cid, ti.GetScope())
+		app := &model.Application{}
+		if err := m.db.GetWhere("client_id", cid, app); err != nil {
+			l.Tracef("no app found for client %s", cid)
+		}
+		c.Set(oauth.SessionAuthorizedApplication, app)
+		l.Tracef("set gin context %s to %+v", oauth.SessionAuthorizedApplication, app)
+	}
+}
diff --git a/internal/apimodule/auth/signin.go b/internal/apimodule/auth/signin.go
new file mode 100644
index 000000000..34146cbfc
--- /dev/null
+++ b/internal/apimodule/auth/signin.go
@@ -0,0 +1,115 @@
+/*
+   GoToSocial
+   Copyright (C) 2021 GoToSocial Authors admin@gotosocial.org
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU Affero General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU Affero General Public License for more details.
+
+   You should have received a copy of the GNU Affero General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+package auth
+
+import (
+	"errors"
+	"net/http"
+
+	"github.com/gin-contrib/sessions"
+	"github.com/gin-gonic/gin"
+	"github.com/superseriousbusiness/gotosocial/internal/db/model"
+	"golang.org/x/crypto/bcrypt"
+)
+
+type login struct {
+	Email    string `form:"username"`
+	Password string `form:"password"`
+}
+
+// signInGETHandler should be served at https://example.org/auth/sign_in.
+// The idea is to present a sign in page to the user, where they can enter their username and password.
+// The form will then POST to the sign in page, which will be handled by SignInPOSTHandler
+func (m *authModule) signInGETHandler(c *gin.Context) {
+	m.log.WithField("func", "SignInGETHandler").Trace("serving sign in html")
+	c.HTML(http.StatusOK, "sign-in.tmpl", gin.H{})
+}
+
+// signInPOSTHandler should be served at https://example.org/auth/sign_in.
+// The idea is to present a sign in page to the user, where they can enter their username and password.
+// The handler will then redirect to the auth handler served at /auth
+func (m *authModule) signInPOSTHandler(c *gin.Context) {
+	l := m.log.WithField("func", "SignInPOSTHandler")
+	s := sessions.Default(c)
+	form := &login{}
+	if err := c.ShouldBind(form); err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
+		return
+	}
+	l.Tracef("parsed form: %+v", form)
+
+	userid, err := m.validatePassword(form.Email, form.Password)
+	if err != nil {
+		c.String(http.StatusForbidden, err.Error())
+		return
+	}
+
+	s.Set("userid", userid)
+	if err := s.Save(); err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+		return
+	}
+
+	l.Trace("redirecting to auth page")
+	c.Redirect(http.StatusFound, oauthAuthorizePath)
+}
+
+// validatePassword takes an email address and a password.
+// The goal is to authenticate the password against the one for that email
+// address stored in the database. If OK, we return the userid (a uuid) for that user,
+// so that it can be used in further Oauth flows to generate a token/retreieve an oauth client from the db.
+func (m *authModule) validatePassword(email string, password string) (userid string, err error) {
+	l := m.log.WithField("func", "ValidatePassword")
+
+	// make sure an email/password was provided and bail if not
+	if email == "" || password == "" {
+		l.Debug("email or password was not provided")
+		return incorrectPassword()
+	}
+
+	// first we select the user from the database based on email address, bail if no user found for that email
+	gtsUser := &model.User{}
+
+	if err := m.db.GetWhere("email", email, gtsUser); err != nil {
+		l.Debugf("user %s was not retrievable from db during oauth authorization attempt: %s", email, err)
+		return incorrectPassword()
+	}
+
+	// make sure a password is actually set and bail if not
+	if gtsUser.EncryptedPassword == "" {
+		l.Warnf("encrypted password for user %s was empty for some reason", gtsUser.Email)
+		return incorrectPassword()
+	}
+
+	// compare the provided password with the encrypted one from the db, bail if they don't match
+	if err := bcrypt.CompareHashAndPassword([]byte(gtsUser.EncryptedPassword), []byte(password)); err != nil {
+		l.Debugf("password hash didn't match for user %s during login attempt: %s", gtsUser.Email, err)
+		return incorrectPassword()
+	}
+
+	// If we've made it this far the email/password is correct, so we can just return the id of the user.
+	userid = gtsUser.ID
+	l.Tracef("returning (%s, %s)", userid, err)
+	return
+}
+
+// incorrectPassword is just a little helper function to use in the ValidatePassword function
+func incorrectPassword() (string, error) {
+	return "", errors.New("password/email combination was incorrect")
+}
diff --git a/internal/apimodule/auth/token.go b/internal/apimodule/auth/token.go
new file mode 100644
index 000000000..1e54b6ab3
--- /dev/null
+++ b/internal/apimodule/auth/token.go
@@ -0,0 +1,36 @@
+/*
+   GoToSocial
+   Copyright (C) 2021 GoToSocial Authors admin@gotosocial.org
+
+   This program is free software: you can redistribute it and/or modify
+   it under the terms of the GNU Affero General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU Affero General Public License for more details.
+
+   You should have received a copy of the GNU Affero General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+package auth
+
+import (
+	"net/http"
+
+	"github.com/gin-gonic/gin"
+)
+
+// tokenPOSTHandler should be served as a POST at https://example.org/oauth/token
+// The idea here is to serve an oauth access token to a user, which can be used for authorizing against non-public APIs.
+// See https://docs.joinmastodon.org/methods/apps/oauth/#obtain-a-token
+func (m *authModule) tokenPOSTHandler(c *gin.Context) {
+	l := m.log.WithField("func", "TokenPOSTHandler")
+	l.Trace("entered TokenPOSTHandler")
+	if err := m.server.HandleTokenRequest(c.Writer, c.Request); err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+	}
+}
diff --git a/internal/apimodule/fileserver/fileserver.go b/internal/apimodule/fileserver/fileserver.go
new file mode 100644
index 000000000..bbafff76f
--- /dev/null
+++ b/internal/apimodule/fileserver/fileserver.go
@@ -0,0 +1,63 @@
+package fileserver
+
+import (
+	"fmt"
+
+	"github.com/sirupsen/logrus"
+	"github.com/superseriousbusiness/gotosocial/internal/apimodule"
+	"github.com/superseriousbusiness/gotosocial/internal/config"
+	"github.com/superseriousbusiness/gotosocial/internal/db"
+	"github.com/superseriousbusiness/gotosocial/internal/db/model"
+	"github.com/superseriousbusiness/gotosocial/internal/router"
+	"github.com/superseriousbusiness/gotosocial/internal/storage"
+)
+
+// fileServer implements the RESTAPIModule interface.
+// The goal here is to serve requested media files if the gotosocial server is configured to use local storage.
+type fileServer struct {
+	config      *config.Config
+	db          db.DB
+	storage     storage.Storage
+	log         *logrus.Logger
+	storageBase string
+}
+
+// New returns a new fileServer module
+func New(config *config.Config, db db.DB, storage storage.Storage, log *logrus.Logger) apimodule.ClientAPIModule {
+
+	storageBase := config.StorageConfig.BasePath // TODO: do this properly
+
+	return &fileServer{
+		config:      config,
+		db:          db,
+		storage:     storage,
+		log:         log,
+		storageBase: storageBase,
+	}
+}
+
+// Route satisfies the RESTAPIModule interface
+func (m *fileServer) Route(s router.Router) error {
+	// s.AttachHandler(http.MethodPost, appsPath, m.appsPOSTHandler)
+	return nil
+}
+
+func (m *fileServer) CreateTables(db db.DB) error {
+	models := []interface{}{
+		&model.User{},
+		&model.Account{},
+		&model.Follow{},
+		&model.FollowRequest{},
+		&model.Status{},
+		&model.Application{},
+		&model.EmailDomainBlock{},
+		&model.MediaAttachment{},
+	}
+
+	for _, m := range models {
+		if err := db.CreateTable(m); err != nil {
+			return fmt.Errorf("error creating table: %s", err)
+		}
+	}
+	return nil
+}
diff --git a/internal/apimodule/mock_ClientAPIModule.go b/internal/apimodule/mock_ClientAPIModule.go
new file mode 100644
index 000000000..85c7b6ac6
--- /dev/null
+++ b/internal/apimodule/mock_ClientAPIModule.go
@@ -0,0 +1,27 @@
+// Code generated by mockery v2.7.4. DO NOT EDIT.
+
+package apimodule
+
+import (
+	mock "github.com/stretchr/testify/mock"
+	router "github.com/superseriousbusiness/gotosocial/internal/router"
+)
+
+// MockClientAPIModule is an autogenerated mock type for the ClientAPIModule type
+type MockClientAPIModule struct {
+	mock.Mock
+}
+
+// Route provides a mock function with given fields: s
+func (_m *MockClientAPIModule) Route(s router.Router) error {
+	ret := _m.Called(s)
+
+	var r0 error
+	if rf, ok := ret.Get(0).(func(router.Router) error); ok {
+		r0 = rf(s)
+	} else {
+		r0 = ret.Error(0)
+	}
+
+	return r0
+}