Mozilla Firefox Proxy Settings

Charles can automatically configure Mozilla Firefox's proxy settings. When the proxy settings are configured, Firefox will use Charles and thus its activity will be visible in Charles. Firefox is configured separately from your OS proxy settings as it uses its own proxy settings independent of your OS.

You can enable the proxy configuration and then choose whether to configure Firefox to use Charles as an HTTP proxy or SOCKS proxy, if the SOCKS Proxy is itself enables on the Proxies tab. See the Proxies tab for information on the differences between HTTP and SOCKS.

The Firefox proxy configuration can be enabled at start up, which is the default behaviour, so that when you start Charles it is ready to be used. Alternatively you can disable this and enable the Firefox proxy settings manually or configure Firefox manually to use Charles with its own proxy settings configuration interface.

Mozilla Firefox Add-on

In order to configure Mozilla Firefox's proxy settings you must install the Charles Autoconfiguration add-on for Mozilla Firefox. You will be notified if the add-on is not installed and prompted to download and install it.

Manually choose profile path

Charles automatically locates your Mozilla Firefox profile for the purposes of configuring the proxy settings. Sometimes Charles may be unable to find your profile directory, although this is extremely rare so you should only use this option if you have no success with auto detection.