Command-line tool

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The Meziantou.Framework.WebPlatform.DevTools.Tool .NET tool runs a DevTools protocol server whose browser is this engine, without writing code. Install it:

dotnet tool install --global Meziantou.Framework.WebPlatform.DevTools.Tool

Start a server on port 9222 (the default) whose pages can load any URL:

Meziantou.Framework.WebPlatform.DevTools.Tool --allow-network

The server prints its WebSocket endpoint (DevTools listening on ws://127.0.0.1:9222/devtools/browser/<id>), as Chromium does, and runs until Ctrl+C. Connect a client to it:

Playwright, in any language: ConnectOverCDPAsync("http://127.0.0.1:9222/") in .NET, chromium.connectOverCDP() in Node.js, Python and Java. The clients read the WebSocket endpoint from /json/version; any version of Playwright can connect.
Puppeteer: puppeteer.connect({ browserURL: "http://127.0.0.1:9222" }), or browserWSEndpoint with the printed endpoint.

See Hosting the server for what the server does with the connections.

Options

Option	Default	Effect
`--host`	`127.0.0.1`	The address to listen on (`0.0.0.0` accepts remote clients)
`--port`	`9222`	The port to listen on (`0` chooses a free port)
`--allow-network`	off	The pages can load the documents and the resources of any URL
`--system-fonts`	off	The pages can use the fonts installed on the machine
`--max-connections`	none	The number of clients connected at the same time (the others wait)

The command reference lists them with the help of the tool.

Without --allow-network, the pages only use the content they are given (page.setContent()) and the responses of the intercepted requests (page.route()). The scripts of the pages run in the process of the server: connect trusted clients only, and load trusted pages only.