Looking for info about Gmail’s chat tech stack
I’ve been working on a chat feature for my web app and I’m curious about what technology Gmail uses to power their real-time messaging. I’ve heard about different approaches like long polling, WebSockets, and server-sent events for building chat applications.
I’m familiar with APE (Ajax Push Engine) which seems like a solid option for real-time communication, but I’m really interested to learn what specific technology or framework Gmail has chosen for their chat functionality. Does anyone know what they use under the hood?
I’m trying to decide between different real-time solutions for my project and understanding how major platforms like Gmail handle this would really help me make the right choice. Any insights would be appreciated!
From what I’ve seen in reverse engineering discussions and Google’s papers, Gmail’s chat has changed a lot over the years. They started with XMPP protocols but switched to their own system - first Hangouts backend, then Google Chat. Now they run on Google’s internal RPC framework (gRPC) plus their global infrastructure. They use persistent connections with custom multiplexing to handle massive scale. The JavaScript client keeps these connections alive through smart reconnection that handles network drops seamlessly. What’s really cool is how they sync messages across devices - they built a distributed system that stays consistent without the WebSocket overhead you’d get in smaller apps. But honestly? For your web app, just use Socket.io or native WebSockets unless you’re planning millions of concurrent users.
I looked into this while building something similar last year. Google ditched their XMPP setup around 2013 and switched to “Tango” - basically persistent HTTP connections that run on their existing infrastructure. They skip WebSockets entirely, which is pretty interesting. Instead, they use long-lived HTTP connections with custom heartbeats and smart fallbacks. This lets them use their CDN and load balancing without dealing with websocket routing issues. They’ve also got this “channel API” thing that handles two-way communication through App Engine. But honestly? Just use WebSockets or Socket.io for your project. Google’s approach needs massive infrastructure that’s not worth it unless you’re running at their scale.
gmail’s chat runs on babel, a custom protocol. they have a unique setup to manage tons of connections simultaneously, which is pretty cool but not something we can mimic easily lol.