diff --git a/lib/pleroma/web/auth/database_authenticator.ex b/lib/pleroma/web/auth/database_authenticator.ex
new file mode 100644
index 000000000..e78068b03
--- /dev/null
+++ b/lib/pleroma/web/auth/database_authenticator.ex
@@ -0,0 +1,20 @@
+# Pleroma: A lightweight social networking server
+# Copyright © 2017-2019 Pleroma Authors <https://pleroma.social/>
+# SPDX-License-Identifier: AGPL-3.0-only
+
+defmodule Pleroma.Web.Auth.DatabaseAuthenticator do
+  alias Pleroma.User
+
+  def implementation do
+    Pleroma.Config.get(
+      Pleroma.Web.Auth.DatabaseAuthenticator,
+      Pleroma.Web.Auth.PleromaDatabaseAuthenticator
+    )
+  end
+
+  @callback get_user(Plug.Conn.t()) :: {:ok, User.t()} | {:error, any()}
+  def get_user(plug), do: implementation().get_user(plug)
+
+  @callback handle_error(Plug.Conn.t(), any()) :: any()
+  def handle_error(plug, error), do: implementation().handle_error(plug, error)
+end
diff --git a/lib/pleroma/web/auth/pleroma_database_authenticator.ex b/lib/pleroma/web/auth/pleroma_database_authenticator.ex
new file mode 100644
index 000000000..39aa1a586
--- /dev/null
+++ b/lib/pleroma/web/auth/pleroma_database_authenticator.ex
@@ -0,0 +1,26 @@
+# Pleroma: A lightweight social networking server
+# Copyright © 2017-2019 Pleroma Authors <https://pleroma.social/>
+# SPDX-License-Identifier: AGPL-3.0-only
+
+defmodule Pleroma.Web.Auth.PleromaDatabaseAuthenticator do
+  alias Pleroma.User
+  alias Comeonin.Pbkdf2
+
+  @behaviour Pleroma.Web.Auth.DatabaseAuthenticator
+
+  def get_user(%Plug.Conn{} = conn) do
+    %{"authorization" => %{"name" => name, "password" => password}} = conn.params
+
+    with {_, %User{} = user} <- {:user, User.get_by_nickname_or_email(name)},
+         {_, true} <- {:checkpw, Pbkdf2.checkpw(password, user.password_hash)} do
+      {:ok, user}
+    else
+      error ->
+        {:error, error}
+    end
+  end
+
+  def handle_error(%Plug.Conn{} = _conn, error) do
+    error
+  end
+end
diff --git a/lib/pleroma/web/oauth/oauth_controller.ex b/lib/pleroma/web/oauth/oauth_controller.ex
index 7c1a3adbd..5c2b0507c 100644
--- a/lib/pleroma/web/oauth/oauth_controller.ex
+++ b/lib/pleroma/web/oauth/oauth_controller.ex
@@ -5,6 +5,7 @@
 defmodule Pleroma.Web.OAuth.OAuthController do
   use Pleroma.Web, :controller
 
+  alias Pleroma.Web.Auth.DatabaseAuthenticator
   alias Pleroma.Web.OAuth.Authorization
   alias Pleroma.Web.OAuth.Token
   alias Pleroma.Web.OAuth.App
@@ -24,27 +25,27 @@ def authorize(conn, params) do
     available_scopes = (app && app.scopes) || []
     scopes = oauth_scopes(params, nil) || available_scopes
 
-    render(conn, "show.html", %{
+    template = Pleroma.Config.get(:auth_template, "show.html")
+
+    render(conn, template, %{
       response_type: params["response_type"],
       client_id: params["client_id"],
       available_scopes: available_scopes,
       scopes: scopes,
       redirect_uri: params["redirect_uri"],
-      state: params["state"]
+      state: params["state"],
+      params: params
     })
   end
 
   def create_authorization(conn, %{
         "authorization" =>
           %{
-            "name" => name,
-            "password" => password,
             "client_id" => client_id,
             "redirect_uri" => redirect_uri
           } = auth_params
       }) do
-    with %User{} = user <- User.get_by_nickname_or_email(name),
-         true <- Pbkdf2.checkpw(password, user.password_hash),
+    with {_, {:ok, %User{} = user}} <- {:get_user, DatabaseAuthenticator.get_user(conn)},
          %App{} = app <- Repo.get_by(App, client_id: client_id),
          true <- redirect_uri in String.split(app.redirect_uris),
          scopes <- oauth_scopes(auth_params, []),
@@ -53,9 +54,9 @@ def create_authorization(conn, %{
          {:missing_scopes, false} <- {:missing_scopes, scopes == []},
          {:auth_active, true} <- {:auth_active, User.auth_active?(user)},
          {:ok, auth} <- Authorization.create_authorization(app, user, scopes) do
-      # Special case: Local MastodonFE.
       redirect_uri =
         if redirect_uri == "." do
+          # Special case: Local MastodonFE
           mastodon_api_url(conn, :login)
         else
           redirect_uri
@@ -97,7 +98,7 @@ def create_authorization(conn, %{
         |> authorize(auth_params)
 
       error ->
-        error
+        DatabaseAuthenticator.handle_error(conn, error)
     end
   end
 
diff --git a/lib/pleroma/web/web.ex b/lib/pleroma/web/web.ex
index 853aa2a87..66813e4dd 100644
--- a/lib/pleroma/web/web.ex
+++ b/lib/pleroma/web/web.ex
@@ -26,6 +26,12 @@ def controller do
       import Plug.Conn
       import Pleroma.Web.Gettext
       import Pleroma.Web.Router.Helpers
+
+      plug(:set_put_layout)
+
+      defp set_put_layout(conn, _) do
+        put_layout(conn, Pleroma.Config.get(:app_layout, "app.html"))
+      end
     end
   end