question

We don't have a direct WeChat integration currently (Aug 2017), but if that's something you'd like to see, I'd recommend adding it to our Feature Requests forum, so that others can vote on it. In the short term, you could use our internal friends list for this by adding any unique player ID you can get from another service as a Generic ID, which you could then use as the lookup, in order to add those players to the local player's friends list:

https://api.playfab.com/documentation/client/method/AddGenericID

https://api.playfab.com/documentation/client/method/GetPlayFabIDsFromGenericIDs

Please be aware that you'll need to throttle the calls to add friends, so that you're not attempting to hit the service with hundreds (or thousands) of AddFriend calls from a single player. Waiting a few seconds after each AddFriend request should prevent throttling of your title in the service.