notep4d.com

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Overview

Notep4d turns any URL into a live collaborative notepad. Visit notep4d.com/anything and you instantly have a shared document — anyone with the link can edit simultaneously and see every keystroke in real time.

I built it because I was developing on a remote Linux server and wanted a fast way to move text between machines without dealing with SSH or account setup. Just open a link, paste, and grab it from the other side.

Architecture

The backend is a Go server using Gorilla WebSocket. Each URL path maps to a room managed by a central hub. When a client connects, they receive the full document history and a randomly assigned animal-themed username. The hub broadcasts binary messages (document updates) to all clients and relays text messages to everyone except the sender.

On the client side, conflict-free editing is handled by Yjs, a CRDT library. Each user’s edits are encoded as Yjs updates and sent over the WebSocket as binary frames. The server stores and replays the update history so new joiners see the current document state.

Stack: Go $\cdot$ Gorilla WebSocket $\cdot$ Yjs $\cdot$ Vanilla JS