diff --git a/config/config.exs b/config/config.exs
index e82be39..6aa2d8c 100644
--- a/config/config.exs
+++ b/config/config.exs
@@ -1,33 +1,38 @@
 # This file is responsible for configuring your application
 # and its dependencies with the aid of the Mix.Config module.
 use Mix.Config
 
 # This configuration is loaded before any dependency and is restricted
 # to this project. If another project depends on this project, this
 # file won't be loaded nor affect the parent project. For this reason,
 # if you want to provide default values for your application for
 # 3rd-party users, it should be done in your "mix.exs" file.
 
 # You can configure for your application as:
 #
 #     config :kolab_wopi, key: :value
 #
 # And access this configuration in your application as:
 #
 #     Application.get_env(:kolab_wopi, :key)
 #
 # Or configure a 3rd-party app:
 #
 #     config :logger, level: :info
 #
 
 # It is also possible to import configuration files, relative to this
 # directory. For example, you can emulate configuration per environment
 # by uncommenting the line below and defining dev.exs, test.exs and such.
 # Configuration from the imported file will override the ones defined
 # here (which is why it is important to import them last).
 #
 #     import_config "#{Mix.env}.exs"
 
 config :kolab_wopi,
+  host_info: [
+               endpoint_desc: "Kolab Systems, Zurich",
+               machine_name: to_string(Node.self()),
+               version: "kolab_wopi_v" <> to_string(Keyword.get(Mix.Project.get!().project(), :version)) #:application.get_key(:kolab_wopi, :description))
+             ],
   chwala_base_url: "http://localhost/chwala/api/"
diff --git a/lib/kolab_wopi/api.ex b/lib/kolab_wopi/api.ex
index 60d6822..4256461 100644
--- a/lib/kolab_wopi/api.ex
+++ b/lib/kolab_wopi/api.ex
@@ -1,92 +1,113 @@
 defmodule KolabWopi.API do
   @moduledoc """
     An implementation of the Web Application Open Platform Interface (WOPI) API.
 
     See https://wopi.readthedocs.io/en/latest/
   """
 
   use Plug.Router
   use Plug.Debugger
 
   require Logger
 
   plug Plug.Logger
+  plug :wopi_headers
   plug :access_token_handler
   plug :match
   plug :dispatch
 
   def init(options) do
     options
   end
 
   def start_link do
     {:ok, _} = Plug.Adapters.Cowboy.http __MODULE__, []
   end
 
   forward "/wopi/files",       to: __MODULE__.Files
   forward "/wopi/containers",  to: __MODULE__.Containers
   forward "/wopi/ecosystem",   to: __MODULE__.Ecosystem
   forward "/wopibootstrapper", to: __MODULE__.Bootstrap
 
   match _ do
     send_status_resp(conn, 404)
   end
 
 
+  @doc """
+    Plug that adds the standard WOPI response headers
+
+    @see https://wopirest.readthedocs.io/en/latest/common_headers.html
+  """
+  def wopi_headers(conn, _opts) do
+    host_info = Application.get_env(:kolab_wopi, :host_info)
+    conn
+    |> put_resp_header("X-WOPI-HostEndpoint", Keyword.get(host_info, :endpoint_desc))
+    |> put_resp_header("X-WOPI-MachineName", Keyword.get(host_info, :machine_name))
+    |> put_resp_header("X-WOPI-ServerVersion", Keyword.get(host_info, :version))
+  end
+
   @doc """
     Plug that fetches query parameters and validates the access_token.
 
     The access_token parameter is required in every WOPI request.
     If it's missing "401 Unauthorized" response will be send and
     request processing aborted.
   """
   def access_token_handler(conn, _opts) do
     conn = Plug.Conn.fetch_query_params(conn)
     token = conn.query_params["access_token"]
     check_token(conn, token)
   end
 
   # valid token handler
   defp check_token(conn, token) when is_binary(token) and byte_size(token) > 0 do
     assign(conn, :access_token, token)
   end
 
   # invalid token handler
   defp check_token(conn, _) do
       conn
         |> send_status_resp(401)
         |> halt()
   end
 
   @doc """
     Sends the response with setting status code.
 
     It supports Chwala status codes.
   """
-  def send_status_resp(conn, code, reason \\ nil)
+  def send_status_resp(conn, code, reason \\ "Unknown error")
 
   def send_status_resp(conn, 403, reason) do
     # Chwala uses only 200, 403, 500, 501, 503
     send_status_resp(conn, 401, reason)
   end
 
+  def send_status_resp(conn, code, reason) when code >= 500 and code < 600 do
+    # TODO: log status reason?
+    conn
+        |> put_resp_header("X-WOPI-ServerError", reason)
+        |> send_resp(code, "")
+  end
+
   def send_status_resp(conn, code, _reason) do
     # TODO: log status reason?
     send_resp(conn, code, "")
   end
 
   @doc """
     Return X-WOPI-Override header value.
 
     With some buggy collabora versions support.
   """
   def get_wopi_action(conn) do
     action =
       case get_req_header(conn, "x-wopi-override") do
         a when length(a) > 0 -> a
         _ -> get_req_header(conn, "x-wopioverride")
       end
 
     to_string(action)
   end
 end