The endpoint you found, https://games.roblox.com/v1/games/{gameId}/favorites?userId={userId}, is indeed part of Roblox’s API, but it’s not officially documented for public use. This means it might work, but it could also be subject to change without notice, which can break your implementation
Using this endpoint directly from your game via HttpService is against Roblox’s Terms of Service because HttpService cannot make requests to Roblox domains directly. Instead, you would need to set up a proxy server to handle these requests. Read this if you want to know more!
Here are some steps you can follow:
Set up a proxy server: You can use a service like Heroku, AWS, or any other hosting service to create a simple server that forwards requests to the Roblox API.
Make requests from your game to the proxy server: Use HttpService in your Roblox game to send requests to your proxy server, which will then forward them to the Roblox API.
If you prefer to stay within the bounds of Roblox’s official APIs, you might need to look for alternative methods or wait for Roblox to provide a more stable and documented API for checking game favorites.