Cloudflare Launches New Tool h3i for HTTP/3 Testing & Debugging

Cloudflare introduced h3i, an open-source command-line tool and Rust library for low-level testing and debugging of HTTP/3, enabling developers to validate protocol compliance and robustness. Key features include an interactive CLI, qlog-based record-and-replay, support for crafting malformed requests to probe edge cases, and automation via a Rust API. The tool aims to improve interoperability and security of HTTP/3 deployments, with future plans to expand capabilities (e.g., HTTP/2 testing).