CURLOPT_PROXY_SSLCERTTYPE - type of the proxy client SSL certificate

Added in curl 7.52.0

"PEM"

Pass a pointer to a null-terminated string as parameter. The string should be the format of your client certificate used when connecting to an HTTPS proxy. Supported formats are "PEM" and "DER", except with Secure Transport or Schannel. OpenSSL (versions 0.9.3 and later), Secure Transport (on iOS 5 or later, or macOS 10.7 or later) and Schannel support "P12" for PKCS#12-encoded files. 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.

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_SSLCERTTYPE, "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); } }

CURLOPT_PROXY_SSLCERTTYPE - type of the proxy client SSL certificate

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

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).

CURLOPT_PROXY_SSLCERT(3), CURLOPT_PROXY_SSLKEY(3), CURLOPT_SSLCERTTYPE(3) libcurl 2025-06-16 CURLOPT_PROXY_SSLCERTTYPE(3)

#include <curl/curl.h> CURLcode curl_easy_setopt(CURL *handle, CURLOPT_PROXY_SSLCERTTYPE, char *type);