CLOUDFLARE has announced a major upgrade to its software stack, replacing the long-running FL1 with a Rust-based FL2 built on the Oxy framework to boost speed and security. The update, shared on 26 September 2025, claims a median 10 ms improvement in response time and a 25% overall performance boost, with FL2 using less CPU and memory than FL1.
The migration involves reorganising product logic into modular Rust-based components and introduces graceful restarts, systemd socket activation, and a restart coordination mechanism to minimise disruption during deployments. Cloudflare says the migration is already underway, with customer traffic being rolled through FL2 throughout 2025, aiming to disable FL1 in early 2026, and noting that feature delivery now occurs within 48 hours in FL2 rather than weeks in FL1.
The transition also emphasises enhanced security through Rust’s memory-safety guarantees and a stricter module framework, alongside ongoing testing with an automated rollout process and fallbacks to FL1 if needed. Cloudflare’s broader message highlights how FL2 enables faster, safer delivery of services across its network as it continues to evolve its architecture.