← Workers / workers / observability

DevTools

When running your Worker locally using the Wrangler CLI ↗ (wrangler dev) or using Vite ↗ with the Cloudflare Vite plugin ↗, you automatically have access to Cloudflare's implementation ↗ of Chrome DevTools ↗.

You can use Chrome DevTools to:

• View logs directly in the Chrome console
• Debug code by setting breakpoints
• Profile CPU usage
• Observe memory usage and debug memory leaks in your code that can cause out-of-memory (OOM) errors

• Run your Worker locally, by running wrangler dev
• Press the D key from your terminal to open DevTools in a browser tab

• Run your Worker locally by running vite
• In a new Chrome tab, open the debug URL that shows in your console (for example, http://localhost:5173/__debug)

Both the Cloudflare dashboard ↗ and the Worker's Playground ↗ include DevTools in the UI.

• Local development - Develop your Workers and connected resources locally via Wrangler and workerd, for a fast, accurate feedback loop.