Debugging QUIC and HTTP/3 with qlog and qvis

The QUIC and HTTP/3 protocols are powerful but complex and difficult to debug and analyse. Our previous work proposed the qlog format for structured endpoint logging to aid in taming this complexity. This follow-up study evaluates the real-world implementations, uses and deployments of qlog and our associated qvis tooling in academia and industry. Our survey among 28 QUIC experts shows high community involvement, while Facebook confirms qlog can handle Internet scale. Lessons learned from researching 16 QUIC+HTTP/3 and five TCP+TLS+HTTP/2 implementations demonstrate that qlog and qvis are essential tools for performing root-cause analysis when debugging modern Web protocols.