diff --git a/src/Routes/RouteLogin.c b/src/Routes/RouteLogin.c
index 332d217..6bf49ae 100644
--- a/src/Routes/RouteLogin.c
+++ b/src/Routes/RouteLogin.c
@@ -48,7 +48,7 @@ ROUTE_IMPL(RouteLogin, args)
 
     char *password;
     char *type;
-    char *username;
+    UserId *userId = NULL;
 
     Db *db = args->matrixArgs->db;
 
@@ -160,9 +160,17 @@ ROUTE_IMPL(RouteLogin, args)
                 break;
             }
 
-            username = JsonValueAsString(val);
+            userId = UserParseId(JsonValueAsString(val),
+                                 args->matrixArgs->config->serverName);
+            if (!userId)
+            {
+                HttpResponseStatus(args->context, HTTP_BAD_REQUEST);
+                response = MatrixErrorCreate(M_BAD_JSON);
+                break;
+            }
 
-            if (!UserExists(db, username))
+            if (strcmp(userId->server, args->matrixArgs->config->serverName) != 0
+                || !UserExists(db, userId->localpart))
             {
                 HttpResponseStatus(args->context, HTTP_FORBIDDEN);
                 response = MatrixErrorCreate(M_FORBIDDEN);
@@ -225,7 +233,7 @@ ROUTE_IMPL(RouteLogin, args)
                 refreshToken = JsonValueAsBoolean(val);
             }
 
-            user = UserLock(db, username);
+            user = UserLock(db, userId->localpart);
 
             if (!user)
             {
@@ -284,6 +292,7 @@ ROUTE_IMPL(RouteLogin, args)
             break;
     }
 
+    UserFreeId(userId);
     JsonFree(request);
     return response;
 }
diff --git a/src/User.c b/src/User.c
index 7bb9010..8935658 100644
--- a/src/User.c
+++ b/src/User.c
@@ -598,3 +598,72 @@ UserDeleteToken(User * user, char *token)
 
     return 1;
 }
+
+UserId *
+UserParseId(char *id, char *defaultServer)
+{
+    UserId *userId;
+
+    if (!id)
+    {
+        return NULL;
+    }
+
+    id = StrDuplicate(id);
+    if (!id)
+    {
+        return NULL;
+    }
+
+    userId = Malloc(sizeof(UserId));
+    if (!userId)
+    {
+        goto finish;
+    }
+
+    /* Fully-qualified user ID */
+    if (*id == '@')
+    {
+        char *localStart = id + 1;
+        char *serverStart = localStart;
+
+        while (*serverStart != ':' && *serverStart != '\0')
+        {
+            serverStart++;
+        }
+
+        if (*serverStart == '\0')
+        {
+            Free(userId);
+            userId = NULL;
+            goto finish;
+        }
+
+        *serverStart = '\0';
+        serverStart++;
+
+        userId->localpart = StrDuplicate(localStart);
+        userId->server = StrDuplicate(serverStart);
+    }
+    else
+    {
+        /* Treat it as just a localpart */
+        userId->localpart = StrDuplicate(id);
+        userId->server = StrDuplicate(defaultServer);
+    }
+
+finish:
+    Free(id);
+    return userId;
+}
+
+void 
+UserFreeId(UserId *id)
+{
+    if (id)
+    {
+        Free(id->localpart);
+        Free(id->server);
+        Free(id);
+    }
+}
diff --git a/src/include/User.h b/src/include/User.h
index 3b26af6..a4daa32 100644
--- a/src/include/User.h
+++ b/src/include/User.h
@@ -42,6 +42,12 @@ typedef struct UserLoginInfo
     char *refreshToken;
 } UserLoginInfo;
 
+typedef struct UserId
+{
+    char *localpart;
+    char *server;
+} UserId;
+
 extern int
  UserValidate(char *, char *);
 
@@ -93,4 +99,10 @@ extern void
 extern int
  UserDeleteToken(User *, char *);
 
+extern UserId *
+ UserParseId(char *, char *);
+
+extern void
+ UserFreeId(UserId *);
+
 #endif                             /* TELODENDRIA_USER_H */