node-inspect-debugger

Run `node inspect script.js` to launch paused on the first line, then use `sb('file.js', 42)` to set breakpoints, `cont` to continue, and `repl` to evaluate expressions in the current scope. No extra installation is required since the inspector is built into Node.

Send SIGUSR1 to the process with `kill -SIGUSR1 <pid>` to enable the inspector, then attach with `node inspect -p <pid>` or via the WebSocket URL printed by Node. You can list inspectable targets at http://127.0.0.1:9229/json/list.

node inspect is built-in and best for quick interactive poking via its REPL. chrome-remote-interface is better when you need to automate many breakpoints, capture scope state across runs, or collect CPU profiles and heap snapshots non-interactively.

Breakpoints bind to the emitted JavaScript, not the .ts source. Either set breakpoints in the built dist/*.js files, or run Node with --enable-source-maps and use a CDP client that follows sourcemaps, since the node inspect CLI does not.

The --inspect flag on a parent does not inspect its children. Use NODE_OPTIONS='--inspect-brk' node parent.js to propagate the inspector to every child; Node auto-increments ports so each child gets a unique one.

Avoid it for problems console.log solves in under a minute, since breakpoint sessions are heavier to set up. Also use python-debugpy instead for Python child processes such as PTY bridge workers, which the V8 inspector cannot attach to.