WebDriver BiDi modules

List of modules

• bluetooth
• browser
• browsingContext
• emulation
• input
• log
• network
• permission
• script
• session
• storage
• webExtension

Commands

A command is an asynchronous operation sent from the client to the browser. Each command message has three fields:

• id: A number you assign to the command. Unlike HTTP where each request waits for a response, a WebSocket connection can have multiple commands in flight at the same time and responses may arrive out of order. The id lets you match each response to the command that triggered it.
• method: The command to run, in the form module_name.command_name.
• params: An object with any additional information the command needs. Some commands require no parameters, but an empty params object ({}) must still be sent.

For example, to create a new session, you would send the session.new command as follows:

{
  "id": 1,
  "method": "session.new",
  "params": {}
}

Each command results in either a success response containing a result field or an error response containing an error field. The structure of result is specific to each command.

Most commands require an active session. However, some commands are static — they can run without an active session. For example, the session.status command is static because it can be used to check whether the browser is ready to create a new session before actually creating one.

Events

An event is a notification sent by the browser to the client when something of interest occurs. Unlike commands, the browser sends events on its own, without the client requesting them. Each event message has two fields:

• method: The event name, in the form module_name.event_name.
• params: An object containing data about the event.

To receive events, the client must first subscribe to them using the session.subscribe command. The subscription message has the same id and method fields as any other command, and the params field takes an events array containing the event names to subscribe to:

{
  "id": 2,
  "method": "session.subscribe",
  "params": {
    "events": ["network.responseCompleted"]
  }
}

session.subscribe returns a subscription ID, which can be used with session.unsubscribe to stop receiving those events.

Browser compatibility