What technique does Google Docs use for real-time data synchronization without constant polling?

Other Questions Google docs
1

I’m working on a web app that needs to update data in real time. Right now I’m using a basic approach with setInterval() that calls an AJAX endpoint every few seconds to fetch fresh data and update the DOM.

function updateContent() {
    fetch('/api/latest-updates')
        .then(response => response.json())
        .then(data => {
            document.getElementById('content-area').innerHTML = buildHTML(data);
        });
}

setInterval(updateContent, 3000);

This works but causes browser freezing on slower machines, especially in Firefox and IE. When I check the network tab, I can see Facebook making regular requests every few seconds. But when I look at Google Docs, I don’t see the same pattern of repeated requests.

I’m wondering if Google Docs uses HTTP streaming or WebSockets instead of polling? My app needs to handle thousands of concurrent users, so I want to make sure I’m using the best approach for the client side performance.

Has anyone investigated how major real-time applications handle this? What would be the most efficient way to keep data synchronized without overwhelming the browser?

2

yep, google docs goes for websockets combined with some ops transform stuff. polling can kill ur perf with so many users – calling ur server every 3 secs is a no-go, way better to keep a single connection alive. check out socket.io, it does fallbacks kinda easy.

3

Google Docs uses WebSockets and Server-Sent Events (SSE) based on what your browser supports. Polling will crash and burn with thousands of users.

I hit this same wall building a team dashboard. Constant AJAX calls destroyed server resources and froze browsers.

Switching to event-driven architecture fixed everything. Instead of clients asking “got updates?” every 3 seconds, the server pushes changes when they happen.

Best part? You can automate the sync without writing WebSocket handlers or managing connection states. Set up triggers that fire on data changes, and updates hit all connected clients instantly.

For thousands of concurrent users, you need something that scales horizontally and handles persistent connections without infrastructure headaches.

I automated this workflow and our real-time features work perfectly across all browsers. No polling, no freezing, way better performance.

Check out Latenode for real-time sync systems: https://latenode.com

4

Google Docs uses WebSockets for real-time collaboration, which provides a more efficient approach than traditional polling methods. I implemented a similar solution in my document editing application and observed a significant improvement in performance. WebSockets maintain a persistent connection for instant updates, eliminating the need for frequent HTTP requests. For those interested, you can check the Chrome DevTools during a session in Google Docs and view the active WebSocket connection in the Network tab. For scalability with thousands of concurrent users, starting with WebSockets and incorporating operational transforms for conflict resolution is advisable. Libraries like Socket.io offer excellent support for handling fallbacks.

5

Google Docs uses WebSockets with operational transformation, but here’s what most people don’t know - they also run a differential sync protocol that batches and compresses changes super efficiently. Your polling setup will definitely hit a wall at scale since every request adds overhead even when nothing’s changed. I built something similar for financial data and found out Google actually keeps client-side shadow copies to cut down network traffic. They maintain three document states: client version, shadow copy, and server version. Only the differences between shadows get sent, which massively reduces bandwidth compared to syncing entire documents. For thousands of users, I’d go with WebSocket connections that have heartbeat mechanisms and fall back to Server-Sent Events when WebSockets fail. The trick is ditching the request-response cycle completely - let the server reach out when changes actually happen.

6

Google Docs uses a hybrid approach - WebSockets plus operational transformation algorithms and differential sync. I’ve reverse-engineered their network traffic, and they keep persistent connections but also have conflict resolution that’s way more advanced than basic WebSocket setups. The big difference from your polling method? Google sends delta changes, not full document states. When multiple users edit at once, each keystroke creates a small operational transform that gets broadcast to other clients. Your setInterval setup will definitely hurt scalability. I ran into the same browser freezing when I built a collaborative whiteboard. Fixed it with event-driven updates - the server only pushes changes when they actually happen, plus client-side buffering for rapid updates. For thousands of concurrent users, you’ll need connection pooling and probably a message queue system to distribute load across multiple server instances.