Connect my app to API and Build me a messaging app using an sdk

I have a video calling app and i want you to connect it to an API message me to learn what API it is, add an auth to my app, deploy it to heroku for back end and vercel for front end when done, ill give you the source code or invite you, for the messaging i need an auth use an SDK provider we can discuss how this project can work. must have experience for web development knows api and sdk.