A SOCKS proxy is an alternative to an HTTP proxy. SOCKS is multi-protocol in that it can support proxying any TCP/IP traffic, not just HTTP. Some organisations will use SOCKS proxies to enable non-HTTP applications to bypass a firewall; often an HTTP proxy will be provided in addition to a SOCKS proxy.

Charles contains a SOCKS proxy as an alternative to or in addition to its HTTP proxy. This enables you to configure applications to use Charles that may not support HTTP proxying but do support SOCKS proxy.

Charles’s SOCKS proxy can be configured in the Proxy Settings in the Proxy menu.

Using Charles as a SOCKS proxy also has some significant advantages over HTTP proxying. See HTTP vs SOCKS proxy.