Dear Sir,
I'm an experienced developer in MERN stack including Hooks, Redux, Saga, Thunk, Axios, OAuth, Social logins, Git, and other related technologies. I'm familiar with Facebook API.
In order for me to work on your existing app, you would need to share the source code or Git repo if you have and add me as a developer in the app setting that you must have created in Facebook developer console.
I'm an independent fulltime freelancer and can help you with your project maintenance and enhancement.
Please contact me to discuss further details.
Look forward to hearing from you.
Best Regards,
Swamy