The Network Monitor shows you all the network requests Firefox makes (for example, when it loads a page, or due to XMLHttpRequests), how long each request takes, and details of each request.

Opening the Network Monitor

There are a few different ways to open the Network Monitor:

Press  Ctrl + Shift + E ( Command + Option + E on a Mac).

  • Select "Network" from the Web Developer menu, (which is a submenu of the Tools menu on OS X and Linux).
  • Click the wrench icon (), which is in the main toolbar or under the Hamburger menu (), then select "Network".

The Network Monitor will appear at the bottom of the browser window. Reload the page to see the requests:

The Network Monitor records network requests any time the Toolbox is open, even if the Network Monitor itself is not selected. This means you can start debugging a page in, for example, the Web Console, then switch to the Network Monitor to see network activity without having to reload the page.

UI overview

The UI is divided into four main pieces:

Performance analysis view

Working with the network monitor

The following articles cover different aspects of using the network monitor: