diff --git a/app/controllers/LilaController.scala b/app/controllers/LilaController.scala
index a4c970d636..a1f8845100 100644
--- a/app/controllers/LilaController.scala
+++ b/app/controllers/LilaController.scala
@@ -168,6 +168,15 @@ private[controllers] trait LilaController
   protected def authorizationFailed(req: RequestHeader): SimpleResult =
     Forbidden("no permission")
 
+  private val AcceptApi = play.api.mvc.Accepting("application/vnd.lichess.v1+json")
+  protected def negotiate(html: => Fu[SimpleResult], api: => Fu[SimpleResult])(implicit ctx: Context): Fu[SimpleResult] = {
+    implicit val req = ctx.req
+    render.async {
+      case AcceptApi() => api
+      case _           => html
+    }
+  }
+
   protected def reqToCtx(req: RequestHeader): Fu[HeaderContext] =
     restoreUser(req) map { lila.user.UserContext(req, _) } flatMap { ctx =>
       pageDataBuilder(ctx) map { Context(ctx, _) }
diff --git a/app/controllers/Lobby.scala b/app/controllers/Lobby.scala
index c8990b58f3..8db6a63d92 100644
--- a/app/controllers/Lobby.scala
+++ b/app/controllers/Lobby.scala
@@ -27,7 +27,7 @@ object Lobby extends LilaController {
   def handleStatus(req: RequestHeader, status: Results.Status): Fu[SimpleResult] =
     reqToCtx(req) flatMap { ctx => renderHome(status)(ctx) }
 
-  def renderHome[A](status: Results.Status)(implicit ctx: Context): Fu[SimpleResult] =
+  def renderHome(status: Results.Status)(implicit ctx: Context): Fu[SimpleResult] =
     Env.current.preloader(
       posts = Env.forum.recent(ctx.me, Env.team.cached.teamIds),
       tours = Env.tournament enterable true,
diff --git a/app/controllers/Setup.scala b/app/controllers/Setup.scala
index 6586cd7247..b4ea2259f0 100644
--- a/app/controllers/Setup.scala
+++ b/app/controllers/Setup.scala
@@ -1,7 +1,7 @@
 package controllers
 
 import play.api.data.Form
-import play.api.mvc.{ SimpleResult, Call, RequestHeader }
+import play.api.mvc.{ SimpleResult, Results, Call, RequestHeader, Accepting }
 
 import lila.api.{ Context, BodyContext }
 import lila.app._
@@ -10,14 +10,14 @@ import lila.game.{ GameRepo, Pov, AnonCookie }
 import lila.user.UserRepo
 import views._
 
-object Setup extends LilaController with TheftPrevention {
+object Setup extends LilaController with TheftPrevention with play.api.http.ContentTypes {
 
   private def env = Env.setup
 
   def aiForm = Open { implicit ctx =>
     if (HTTPRequest isXhr ctx.req)
       env.forms aiFilled get("fen") map { form =>
-        html.setup.ai(form, Env.ai.aiPerfApi.intRatings )
+        html.setup.ai(form, Env.ai.aiPerfApi.intRatings)
       }
     else fuccess {
       Redirect(routes.Lobby.home + "#ai")
@@ -174,9 +174,15 @@ object Setup extends LilaController with TheftPrevention {
     OpenBody { implicit ctx =>
       implicit val req = ctx.body
       form(ctx).bindFromRequest.fold(
-        f => fuloginfo(f.errors.toString) inject Redirect(routes.Lobby.home),
-        config => op(config)(ctx) map {
-          case (pov, call) => redirectPov(pov, call)
+        f => negotiate(
+          html = fuloginfo(f.errors.toString) >> Lobby.renderHome(Results.BadRequest),
+          api = fuccess(BadRequest(f.errorsAsJson))
+        ),
+        config => op(config)(ctx) flatMap {
+          case (pov, call) => negotiate(
+            html = fuccess(redirectPov(pov, call)),
+            api = fuccess(Created(lila.api.Json.pov(pov)) as JSON)
+          )
         }
       )
     }
diff --git a/modules/api/src/main/Json.scala b/modules/api/src/main/Json.scala
new file mode 100644
index 0000000000..f0b89b535b
--- /dev/null
+++ b/modules/api/src/main/Json.scala
@@ -0,0 +1,23 @@
+package lila.api
+
+import play.api.http.ContentTypes.JSON
+import play.api.libs.json.{ JsObject, Json => J }
+import play.api.mvc.Results.Ok
+
+import chess.format.Forsyth
+import lila.game.{ Game, Pov }
+
+object Json {
+
+  def pov(p: Pov) = J.obj(
+    "game" -> game(p.game),
+    "player" -> player(p))
+
+  private def game(g: Game) = J.obj(
+    "id" -> g.id,
+    "fen" -> (Forsyth >> g.toChess))
+
+  private def player(p: Pov) = J.obj(
+    "id" -> p.fullId,
+    "color" -> p.color.name)
+}