diff --git a/server/auth.go b/server/auth.go
index 37a318a83..0a9fb369a 100644
--- a/server/auth.go
+++ b/server/auth.go
@@ -80,6 +80,9 @@ func buildAuthPayload(user *model.User) map[string]any {
 	if conf.Server.EnableGravatar && user.Email != "" {
 		payload["avatar"] = gravatar.Url(user.Email, 50)
 	}
+	if tag := user.AvatarTag(); tag != "" {
+		payload["avatarTag"] = tag
+	}
 
 	bytes := make([]byte, 3)
 	_, err := rand.Read(bytes)
diff --git a/server/auth_test.go b/server/auth_test.go
index e021c82a8..518e148c8 100644
--- a/server/auth_test.go
+++ b/server/auth_test.go
@@ -216,6 +216,18 @@ var _ = Describe("Auth", func() {
 				Expect(parsed["token"]).ToNot(BeEmpty())
 			})
 		})
+
+		Describe("buildAuthPayload", func() {
+			It("includes avatarTag when the user has an uploaded avatar", func() {
+				u := &model.User{ID: "u1", UserName: "deluan", UploadedImage: "u1_deluan.png", UpdatedAt: time.Unix(1000, 0)}
+				Expect(buildAuthPayload(u)["avatarTag"]).To(Equal(u.AvatarTag()))
+			})
+
+			It("omits avatarTag when there is none", func() {
+				u := &model.User{ID: "u1", UserName: "deluan"}
+				Expect(buildAuthPayload(u)).ToNot(HaveKey("avatarTag"))
+			})
+		})
 	})
 
 	Describe("tokenFromHeader", func() {