Subtrace

Subtrace is a zero-code network tracer for backend servers. Started with a single command, it captures every incoming and outgoing HTTP request in real time - payload, headers, latency, and status - and shows them in a Chrome DevTools-style interface. It uses eBPF to do this without code changes or root privileges, so engineers can find, inspect, and replay production requests instead of grepping through scattered logs. The tool is open source (BSD-3-Clause) and came out of Y Combinator's Winter 2025 batch.