IMPORTANT: You need to fill in your proxy server details on the addon's options page before use (see the screenshot). Switch between a direct internet connection and using a proxy server with a single click on the toolbar icon or the keyboard shortcut (Ctrl+Shift+Y by default). This addon overrides the standard Firefox proxy settings, so don't expect to use both. Features include: -

Support for HTTP/HTTPS/SOCKS4/SOCKS5 proxy types
Username/password authentication
Remote DNS (SOCKS only)
Option to skip proxy for local network addresses

This is intended to be a simple addon that's easy to configure. I don't plan to add support for additional features (e.g. multiple proxy servers, exceptions), so please look elsewhere for those. The icon will change to match your theme colours if you set "svg.context-properties.content.enabled" to true in about:config (without that setting only Mozilla addons can do this). Since 1.2.1 the addon requires the scary sounding "Access your data for all websites" permission. This is because we've switched to using the new proxy.onRequest method rather than PAC files, so need to know when any request is made to any URL in order to have the opportunity to proxy it. The previous method is being removed in Firefox 71, so this is a necessary change. Users are welcome to review the source code by downloading the addon .xpi and changing the extension to .zip. None of it is in any way obfuscated. You can contact me via the linked support site for any specific issues or bugs.