Works with Express and other Node HTTP servers. Request spans are published by middleware inside the recorded process.
Record your server
ct record --server --lang javascript -o ./trace -- node server.js --port 3000Flags after the program name reach Node unchanged. Stop with Ctrl-C.
Watch requests arrive
In a second terminal:
ct replay -t ./traceSend traffic:
curl http://localhost:3000/users/7Double-click a row to jump into the route handler that served it.
Open a recording later
ct replay ./traceWhat gets recorded
- **Route patterns** rather than concrete paths, so requests to one endpoint
group together.
- **Status and duration** per request.
- **Errors**, including the message for requests that threw.
Concurrent requests
Node serves requests concurrently on one thread, interleaving them at every await. CodeTracer follows the asynchronous execution context, so each request's span covers *its own* work rather than whatever happened to run between its start and end. Two requests that overlap in wall-clock time produce two correctly separated rows.
Requirements
Node.js 20 or newer.
ct record app.js also works for ordinary, non-server scripts. If you have used it before and found that recordings appeared empty, that was an import resolution bug affecting node_modules; it is fixed.
Browser applications
This page covers server-side Node. To record a front-end application running in a browser, see Recording a browser app, which uses a different mechanism.
