Bun Profiling & Debugging

Bun ships with built-in profilers that output standard formats compatible with Chrome DevTools, plus Markdown reports for terminal and LLM-friendly analysis.

What's new in Bun 1.4

• --cpu-prof-md — CPU profile as Markdown for terminal/LLM analysis (1.3.7)
• --heap-prof-md — Heap profile as Markdown (1.3.7)
• BUN_CPU_PROFILE=1 — Profile processes you can't pass flags to (1.4.0)
• node:inspector Profiler API — start/stop CPU profiles programmatically (1.4.0)
• Async stack traces — errors from async APIs point to the await in your code (1.3.12)
• process.on("memoryPressure") — OS memory pressure events (1.4.0)
• --no-orphans — exit when parent dies, SIGKILL descendants (1.3.2)

CPU Profiling

CLI: .cpuprofile for Chrome DevTools