diff --git a/deltachat-ffi/deltachat.h b/deltachat-ffi/deltachat.h
index ef64ed58d..883f720b4 100644
--- a/deltachat-ffi/deltachat.h
+++ b/deltachat-ffi/deltachat.h
@@ -318,6 +318,10 @@ char*           dc_get_blobdir               (const dc_context_t* context);
  *                    The library uses the `media_quality` setting to use different defaults
  *                    for recoding images sent with type DC_MSG_IMAGE.
  *                    If needed, recoding other file types is up to the UI.
+ * - `basic_web_rtc_instance` = address and token to webrtc signaling server (https://github.com/cracker0dks/basicwebrtc)
+ *                    that should be used for calls
+ *                    Format: https://example.com/subdir?token=TOKEN
+ *                    The other properties that are needed for a call such as the roomname will be set in the anchor part of the url.
  *
  * If you want to retrieve a value, use dc_get_config().
  *
diff --git a/src/config.rs b/src/config.rs
index 950602da6..e67144dc5 100644
--- a/src/config.rs
+++ b/src/config.rs
@@ -123,6 +123,9 @@ pub enum Config {
     /// because we do not want to send a second warning)
     NotifyAboutWrongPw,
 
+    /// webrtc signaling server (https://github.com/cracker0dks/basicwebrtc) that should be used for calls
+    /// Format: https://example.com/subdir?token=TOKEN
+    /// The other properties that are needed for a call such as the roomname will be set in the anchor part of the url.
     BasicWebRTCInstance,
 }