You can use the Yelp Fusion API with any OAuth implementation. To simplify the process and maintain a clean project, you can use an OAuth package.
You can find a list of OAuth packages for composer here.
Using packages instead of custom PHP files would help to keep project clean.
If you do need to add any custom PHP files, it's recommended to create a directory within the /app
directory for organization. A good directory name could be "Libraries" or "Helpers," depending on the type of content being stored.
Note that directories and files within the /app
directory are automatically loaded by Composer.