The easiest way to profile web pages is by using the Blackfire Companion for Firefox. The Companion lets you profile the current web page displayed in your browser in a click.

Installing the Companion

Install the Blackfire Companion from the Mozilla Add-On website.

Using the Companion

To profile web pages:

  • Log in on;
  • Browse to the URL you want to profile;
  • Open the Companion by clicking on its icon in the browser toolbar;
  • Click on the "Profile" button;
  • After a few seconds, click on "View Call Graph" or "View Comparison".

Limitations on 304 HTTP Responses

The Companion is not able to profile 304 HTTP responses as some Web Servers remove custom headers such as the ones added by Blackfire to operate correctly. So, to avoid 304 HTTP responses, the Companion removes any conditional headers from requests; if you want to profile 304 responses, use the Blackfire cURL CLI command instead.

Upgrading the Companion

The Firefox extension is automatically updated by the Firefox Scheduler.