Configure Proxy Authentication in Postman’s Desktop App
Configure Postman’s custom proxy account separately from an API’s authorization and select the request types that use that route.
Postman’s request authorization is for the API. An intermediary requiring Basic authentication gets its account through the proxy settings.
In the desktop app’s Settings → Proxy page, enable the custom request-proxy configuration. Choose the intermediary’s protocol, then enter its hostname and port separately. Keep the protocol out of the hostname field.
Enable proxy authentication and enter the intermediary’s username and password there. Select HTTP requests, HTTPS requests or both according to the intended route. A comma-separated bypass list can keep selected hosts direct.
When both system and custom request-proxy options are enabled, the custom configuration wins. Check that choice before changing an otherwise correct system proxy.
The desktop app also has a default-proxy authentication configuration for its system-derived route. Choose the section corresponding to the policy actually used.
A SOCKS option does not turn Postman into a generic TCP tunnel client: its documented SOCKS support carries HTTP and HTTPS requests. Likewise, a request’s manually added Proxy-Authorization header is not a replacement for selecting and authenticating the connection’s intermediary.