FAQ

[paulirish]

Just wrote a few FAQ entries that I'll add to the site soon. Capturing here for the moment:

How is the protocol defined?

The canonical protocol definitions live in the Chromium source tree: (browser_protocol.json and js_protocol.json). They are maintained manually by the DevTools engineering team. These files are mirrored (hourly) on GitHub in the devtools-protocol repo.

The declarative protocol definitions are used across tools. Within Chromium, a binding layer is created for the Chrome DevTools to interact with, and separately the protocol is used for Chrome Headless's C++ interface.

What's the protocol_externs file?

It's created via generate_protocol_externs.py and useful for tools using closure compiler. The TypeScript story is here.

Are the HTTP endpoints documented?

Not yet. See bugger-daemon's third-party docs. See also the endpoints implementation in Chromium. /json/protocol was added in Chrome 60.

How do I access the browser target?

The endpoint is exposed as webSocketDebuggerUrl in /json/version. Note the browser in the URL, rather than page. If Chrome was launched with --remote-debugging-port=0 and chose an open port, the browser endpoint is written to both stderr and the DevToolsActivePort file in browser profile folder.

[nojvek]

@paulirish I'm happy to put up a PR to bring the devtools protocol to typescript interface generator inside this repo if you are interested.

Since npm now supports types field right inside package.json, this should make things even easier to consume the protocol.

[paulirish]

@nojvek yes that'd be awesome. :)

[paulirish]

updated (and correct) answers for all of this are now on https://chromedevtools.github.io/devtools-protocol/