Cloudflare Dynamic Workers: Sandbox AI Code 100x Faster

On April 9, 2026 Cloudflare opened the public beta of Dynamic Workers, a Worker Loader API that spins up a sandboxed V8 isolate per request — roughly 100x faster than booting a container. For agent builders this is huge: when an LLM emits TypeScript at runtime, you no longer have to hand it to Docker and wait 500ms for a cold start. You hand it to env.LOADER and it runs in single-digit milliseconds, with no network access unless you grant it.

This guide walks you through wiring a Worker Loader binding, executing untrusted LLM-generated code, exposing scoped RPC tools to the sandbox, and bundling npm dependencies on the fly. By the end you'll have a working tool-execution sandbox you can drop into any agent loop.