Cloudflare just got faster and more secure, powered by Rust
9/26/2025 · Richard Boulton, Steve Goldsmith, Maurizio Abba, Matthew Bullock
What this post added
This post details the development of FL2, a new implementation of Cloudflare's core request processing logic (FL), written in Rust using the Oxy framework. It replaces the legacy Nginx/LuaJIT-based FL1 system. Key technical contributions include the use of Rust for improved safety and performance, the Oxy framework for proxy development, a strict module framework for rigid modularization of product logic, and enhanced graceful restart capabilities leveraging systemd socket activation and a new Rust-based coordination mechanism called 'shellflip'. The post also outlines the design principles of FL2's module system, emphasizing explicit interactions and a defined order of phases.