Recent advancements in Cloudflare Python Workers means fast cold starts, comprehensive package support, and a great developer experience. We explain how they were achieved and show how Python can be used to build serverless applications on Cloudflare.

Cloudflare's platform is a leading provider of internet security and performance solutions, offering insights into web security, content delivery, and DNS management. Through documentation, blog posts, and webinars, Cloudflare provides insights into protecting websites and applications from cyber threats and improving performance. Developers and IT professionals can learn about CDN (Content Delivery Network), DDoS mitigation, and firewall configurations to secure and accelerate web traffic.

Cloudflare

Cloudflare Python Workers now support any Pyodide-compatible package with significantly faster cold starts than competitors. Using memory snapshots and WebAssembly architecture, Workers achieve 2.4x faster cold starts than AWS Lambda and 3x faster than Google Cloud Run when loading common packages. The platform integrates with uv for package management through pywrangler tooling, enabling easy deployment of Python applications globally. Technical innovations include memory snapshot restoration, careful entropy handling for randomness, and function pointer table management to eliminate Python initialization overhead during cold starts.

Python Workers redux: fast cold starts, packages, and a uv-first workflow

Faster package cold starts than Lambda and Cloud Run

Decreasing cold start duration using snapshots

Reducing cold start frequency using sharding