Full-Stack

Clipboard

A shared text clipboard, synced live across devices by a six-character code

Project Overview

Open a clipboard with a six-character code, paste something in, and it appears instantly on every other device using that code — no account, no install. Runs entirely on Cloudflare: a Worker serves the React SPA and the API, and a Durable Object holds each clipboard's SQLite-backed entries and its live WebSocket connections, one instance per code.

Key Features

Six-character board codes from a 31-character alphabet, no ambiguous I/L/O/0/1
Live fan-out to every connected device over hibernatable WebSockets
Entries expire on their own — 5 minutes to 30 days, oldest evicted past 50 per board
No account, no install — open a board, paste, read it on the next device

Project Writeup

Overview

Open a clipboard with a six-character code, paste something in, and it appears instantly on every other device using that code. No account, no install — entries expire on their own.

Implementation

A Cloudflare Worker serves the React SPA and the API from one deployment.
A Durable Object holds each clipboard's SQLite-backed entries and its live WebSocket connections — one instance per code.
Writes go over HTTP; live pushes come back over a hibernatable WebSocket, so an idle open tab doesn't pin the object in memory or accrue duration charges.
The server broadcasts to every connected socket, including the one that just posted — the client folds messages in idempotently by id so the device that typed them doesn't see a flickering duplicate.

Notes

Six characters from a 31-character alphabet (no ambiguous I/L/O/0/1) is roughly 10⁹ possible codes — fine against guessing a specific one, weak against bulk enumeration, so this stays a shared surface, not a private one.
Text only, no file upload; entries cap at 256 KB, 50 per board.