Trace

A Chrome Trace Event Format performance trace, the format the DevTools Performance panel, chrome://tracing, and Perfetto read. It carries timeline events and a screenshot filmstrip, and one session spans every navigation in the render.

The trace records the page’s renderer process and the browser process. That covers the main frame, same-origin iframes, and worker threads, web workers and service workers alike. Cross-origin iframes render in a process of their own and are excluded, as are the GPU and network-service processes.

Use it as a discrete output (--output-type trace, extension .trace.json) or written alongside another output via --trace.

The trace is gzip-compressed by default. It is written plain only when the path ends .trace.json or --trace-no-gzip is set; over the HTTP API, pass trace_no_gzip to get a plain trace. --trace-no-screenshots drops the filmstrip while keeping the timeline.

When a navigator drives the render, the trace trims to the final destination page by default; --trace-captures-navigation keeps the entire navigation session.

This is a Pro-tier output.