3 files changed, 68 insertions, 10 deletions
diff --git a/internal/api/client/instance/instance.go b/internal/api/client/instance/instance.go
new file mode 100644
index 000000000..ed7c18718
--- /dev/null
+++ b/internal/api/client/instance/instance.go
@@ -0,0 +1,38 @@
+package instance
+
+import (
+	"net/http"
+
+	"github.com/sirupsen/logrus"
+	"github.com/superseriousbusiness/gotosocial/internal/api"
+	"github.com/superseriousbusiness/gotosocial/internal/config"
+	"github.com/superseriousbusiness/gotosocial/internal/message"
+	"github.com/superseriousbusiness/gotosocial/internal/router"
+)
+
+const (
+	// InstanceInformationPath
+	InstanceInformationPath = "api/v1/instance"
+)
+
+// Module implements the ClientModule interface
+type Module struct {
+	config    *config.Config
+	processor message.Processor
+	log       *logrus.Logger
+}
+
+// New returns a new instance information module
+func New(config *config.Config, processor message.Processor, log *logrus.Logger) api.ClientModule {
+	return &Module{
+		config:    config,
+		processor: processor,
+		log:       log,
+	}
+}
+
+// Route satisfies the ClientModule interface
+func (m *Module) Route(s router.Router) error {
+	s.AttachHandler(http.MethodGet, InstanceInformationPath, m.InstanceInformationGETHandler)
+	return nil
+}
diff --git a/internal/api/client/instance/instanceget.go b/internal/api/client/instance/instanceget.go
new file mode 100644
index 000000000..f8e82c096
--- /dev/null
+++ b/internal/api/client/instance/instanceget.go
@@ -0,0 +1,20 @@
+package instance
+
+import (
+	"net/http"
+
+	"github.com/gin-gonic/gin"
+)
+
+func (m *Module) InstanceInformationGETHandler(c *gin.Context) {
+	l := m.log.WithField("func", "InstanceInformationGETHandler")
+
+	instance, err := m.processor.InstanceGet(m.config.Host)
+	if err != nil {
+		l.Debugf("error getting instance from processor: %s", err)
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "internal server error"})
+		return
+	}
+
+	c.JSON(http.StatusOK, instance)
+}
diff --git a/internal/api/model/instance.go b/internal/api/model/instance.go
index 857a8acc5..75ef5392e 100644
--- a/internal/api/model/instance.go
+++ b/internal/api/model/instance.go
@@ -23,9 +23,9 @@ type Instance struct {
 	// REQUIRED
 
 	// The domain name of the instance.
-	URI string `json:"uri"`
+	URI string `json:"uri,omitempty"`
 	// The title of the website.
-	Title string `json:"title"`
+	Title string `json:"title,omitempty"`
 	// Admin-defined description of the Mastodon site.
 	Description string `json:"description"`
 	// A shorter description defined by the admin.
@@ -33,9 +33,9 @@ type Instance struct {
 	// An email that may be contacted for any inquiries.
 	Email string `json:"email"`
 	// The version of Mastodon installed on the instance.
-	Version string `json:"version"`
+	Version string `json:"version,omitempty"`
 	// Primary langauges of the website and its staff.
-	Languages []string `json:"languages"`
+	Languages []string `json:"languages,omitempty"`
 	// Whether registrations are enabled.
 	Registrations bool `json:"registrations"`
 	// Whether registrations require moderator approval.
@@ -43,16 +43,16 @@ type Instance struct {
 	// Whether invites are enabled.
 	InvitesEnabled bool `json:"invites_enabled"`
 	// URLs of interest for clients apps.
-	URLS *InstanceURLs `json:"urls"`
+	URLS *InstanceURLs `json:"urls,omitempty"`
 	// Statistics about how much information the instance contains.
-	Stats *InstanceStats `json:"stats"`
-
-	// OPTIONAL
-
+	Stats *InstanceStats `json:"stats,omitempty"`
 	// Banner image for the website.
-	Thumbnail string `json:"thumbnail,omitempty"`
+	Thumbnail string `json:"thumbnail"`
 	// A user that can be contacted, as an alternative to email.
 	ContactAccount *Account `json:"contact_account,omitempty"`
+	// What's the maximum allowed length of a post on this instance?
+	// This is provided for compatibility with Tusky.
+	MaxTootChars uint `json:"max_toot_chars"`
 }
 
 // InstanceURLs represents URLs necessary for successfully connecting to the instance as a user. See https://docs.joinmastodon.org/entities/instance/