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 is "P12" on Secure Transport and "PEM"
on other engines, and can be changed with CURLOPT_PROXY_SSLCERTTYPE(3).
With Secure Transport, this can also be the nickname of the certificate
you wish to authenticate with as it is named in the security database.
If you want to use a file from the current directory, please precede it
with "./" prefix, in order to avoid confusion with a nickname.
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.
This option works only with the following TLS backends: GnuTLS, OpenSSL,
Schannel, Secure Transport, mbedTLS and wolfSSL
EXAMPLE
int main(void)
{
CURL *curl = curl_easy_init();
if(curl) {
CURLcode res;
curl_easy_setopt(curl, CURLOPT_URL, "https://example.com/");
curl_easy_setopt(curl, CURLOPT_PROXY, "https://proxy");
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");
res = 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), CUR-
LOPT_SSLCERT(3)
libcurl 2026-07-12 CURLOPT_PROXY_SSLCERT(3)
Generated by dwww version 1.16 on Fri Oct 2 13:06:41 CEST 2026.