Minimal Cloudflare Workers Durable Object WebSocket reproduction case for debugging a performance regression between Wrangler 4.31.0 and 4.32.0. From bisecting between these two tags, it looks like this was introduced in d3040550.

If you remove tail_consumers with the nonexistent missing-consumer-xyz from the wrangler.toml, the issue disappears.

• Durable Object accepts WebSocket connections
• Broadcasts JSON messages to all connected clients
• Debug page at / shows cursor positions from all connected browsers

npm install

# Run with wrangler 4.32.0 (bad)
npm run dev-bad

# Run with wrangler 4.31.0 (good)
npm run dev-good

Then open http://localhost:8787 in multiple browser windows and move your cursor.

• src/index.js - Worker and Durable Object code
• wrangler.toml - Cloudflare Workers configuration