REST API for chat develop in Angular or React Native

Hello,

We are having some customers that are wanting to customize some specific functions on chat service (on web page), like letting the customer share GIFs, images, screenshots, share location, etc. So we are thinking on developing the customer side chat on Angular/React for doing this… Is there any REST API for Chat?

Or maybe another way you think this can be done?

Best Regards!

Elias.