CURLOPT_PROXY_SSLCERT(3)   Library Functions Manual   CURLOPT_PROXY_SSLCERT(3)

NAME
       CURLOPT_PROXY_SSLCERT - HTTPS proxy client certificate

SYNOPSIS
       #include <curl/curl.h>

       CURLcode curl_easy_setopt(CURL *handle, CURLOPT_PROXY_SSLCERT, char *cert);

DESCRIPTION
       This option is for connecting to an HTTPS proxy, not an HTTPS server.

       Pass a pointer to a null-terminated string as parameter. The string
       should be the filename of your client certificate used to connect to
       the HTTPS proxy.  The default format "PEM", and can be changed with
       CURLOPT_PROXY_SSLCERTTYPE(3).

       When using a client certificate, you most likely also need to provide a
       private key with CURLOPT_PROXY_SSLKEY(3).

       The application does not have to keep the string around after setting
       this option.

       Using this option multiple times makes the last set string override the
       previous ones. Set it to NULL to disable its use again.

DEFAULT
       NULL

PROTOCOLS
       This functionality affects  all TLS based protocols: HTTPS, FTPS,
       IMAPS, POP3S, SMTPS etc. only

       This option works only with the following TLS backends: GnuTLS,
       OpenSSL, Schannel, mbedTLS and wolfSSL

EXAMPLE
       int main(void)
       {
         CURL *curl = curl_easy_init();
         if(curl) {
           CURLcode result;
           curl_easy_setopt(curl, CURLOPT_URL, "https://example.com/");
           curl_easy_setopt(curl, CURLOPT_PROXY, "https://proxy.example");
           curl_easy_setopt(curl, CURLOPT_PROXY_SSLCERT, "client.pem");
           curl_easy_setopt(curl, CURLOPT_PROXY_SSLKEY, "key.pem");
           curl_easy_setopt(curl, CURLOPT_PROXY_KEYPASSWD, "s3cret");
           result = curl_easy_perform(curl);
           curl_easy_cleanup(curl);
         }
       }

AVAILABILITY
       Added in curl 7.52.0

RETURN VALUE
       curl_easy_setopt(3) returns a CURLcode indicating success or error.

       CURLE_OK (0) means everything was OK, non-zero means an error occurred,
       see libcurl-errors(3).

SEE ALSO
       CURLOPT_PROXY_SSLCERTTYPE(3), CURLOPT_PROXY_SSLKEY(3),
       CURLOPT_SSLCERT(3)

libcurl                           2026-09-02          CURLOPT_PROXY_SSLCERT(3)