---
name: "CURLOPT_PROXYAUTH"
section: "3"
platform: "linux"
package: "curl"
version: "8.23.0-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux", "macos"]
url: "https://new.carta.tech/CURLOPT_PROXYAUTH"
---

# CURLOPT\_PROXYAUTH(3)

HTTP proxy authentication methods

## NAME

CURLOPT\_PROXYAUTH - HTTP proxy authentication methods

## SYNOPSIS

```
#include <curl/curl.h>
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_PROXYAUTH, long bitmask);
```

## DESCRIPTION

Pass a long as parameter, which is set to a bitmask, to tell libcurl which HTTP authentication method(s) you want it to use for your proxy authentication. If more than one bit is set, libcurl first queries the site to see what authentication methods it supports and then it picks the best one you allow it to use. For some methods, this induces an extra network round-trip. Set the actual name and password with the *[CURLOPT\_PROXYUSERPWD(3)](/CURLOPT_PROXYUSERPWD/3.md)* option.

The bitmask can be constructed by the bits listed and described in the *[CURLOPT\_HTTPAUTH(3)](/CURLOPT_HTTPAUTH/3.md)* man page.

Custom *Proxy-Authorization:* headers set with *[CURLOPT\_PROXYHEADER(3)](/CURLOPT_PROXYHEADER/3.md)* may interfere with and cause unintended side-effects if combined with authentication set with *[CURLOPT\_PROXYAUTH(3)](/CURLOPT_PROXYAUTH/3.md)*.

## DEFAULT

CURLAUTH\_BASIC

## PROTOCOLS

This functionality affects all supported protocols

## EXAMPLE

```
int main(void)
{
  CURL *curl = curl_easy_init();
  if(curl) {
    CURLcode result;
    curl_easy_setopt(curl, CURLOPT_URL, "https://example.com/");
    /* use this proxy */
    curl_easy_setopt(curl, CURLOPT_PROXY, "http://local.example.com:1080");
    /* allow whatever auth the proxy speaks */
    curl_easy_setopt(curl, CURLOPT_PROXYAUTH, CURLAUTH_ANY);
    /* set the proxy credentials */
    curl_easy_setopt(curl, CURLOPT_PROXYUSERPWD, "james:007");
    result = curl_easy_perform(curl);
    curl_easy_cleanup(curl);
  }
}
```

## HISTORY

**CURLAUTH\_**\* macros became *long* types in 7.26.0, prior to this version a *long* cast was necessary when passed to *[curl\_easy\_setopt(3)](/curl_easy_setopt/3.md)*.

## AVAILABILITY

Added in curl 7.10.7

## RETURN VALUE

*[curl\_easy\_setopt(3)](/curl_easy_setopt/3.md)* returns a CURLcode indicating success or error.

CURLE\_OK (0) means everything was OK, non-zero means an error occurred, see *[libcurl-errors(3)](/libcurl-errors/3.md)*.

## SEE ALSO

[**CURLOPT\_HTTPAUTH**(3)](/CURLOPT_HTTPAUTH/3.md), [**CURLOPT\_PROXY**(3)](/CURLOPT_PROXY/3.md), [**CURLOPT\_PROXYPORT**(3)](/CURLOPT_PROXYPORT/3.md), [**CURLOPT\_PROXYTYPE**(3)](/CURLOPT_PROXYTYPE/3.md), [**CURLOPT\_PROXYUSERPWD**(3)](/CURLOPT_PROXYUSERPWD/3.md)