What is a Chat API? The Definitive Guide to In-App Messaging (2026)

Building chat looks easy on a whiteboard. You send a string, they get a string. Simple, right? But then reality kicks in. Suddenly, you’re dealing with a user on a shaky 3G connection in a Jakarta basement where packets simply vanish. Then there’s the aggressive battery management on budget Android phones that kills your background process the second a user switches apps—all just to save a tiny bit of "juice." That "instant" message is now stuck in a cross-continent routing loop, adding seconds