node-inspect-debugger

Run node inspect path/to/script.js to launch the built-in debugger paused on the first line. Use sb('file.js', 42) to set breakpoints, c to continue, n to step over, and repl to evaluate expressions in the current scope.

Send SIGUSR1 to the process with kill -SIGUSR1 <pid>, which starts the inspector on port 9229. Then attach with node inspect -p <pid> or connect to the WebSocket URL printed in the output.

--inspect starts the inspector but lets the script run immediately, so early breakpoints may be missed. --inspect-brk pauses execution on the first line, giving you time to set breakpoints before any code runs.

Yes, launch with node --inspect-brk --import tsx script.ts. Note that breakpoints hit the emitted JavaScript lines, not the .ts source, unless you enable sourcemaps with a CDP client that follows them.

Common causes are attaching after execution finished, missing --inspect-brk, or setting breakpoints on TypeScript source lines instead of the compiled output. Verify the target with curl http://127.0.0.1:9229/json/list and check the paused file matches.

Use chrome-remote-interface to enable the Profiler or HeapProfiler domains over CDP. Start profiling, wait, then stop and write the result to a .cpuprofile or .heapsnapshot file for analysis in Chrome DevTools.