.\" generated by cd2nroff 0.1 from CURLOPT_PROXY_SSLKEYTYPE.md
.TH CURLOPT_PROXY_SSLKEYTYPE 3 "2026-06-24" libcurl
.SH NAME
CURLOPT_PROXY_SSLKEYTYPE \- type of the proxy private key file
.SH SYNOPSIS
.nf
#include <curl/curl.h>

CURLcode curl_easy_setopt(CURL *handle, CURLOPT_PROXY_SSLKEYTYPE, char *type);
.fi
.SH 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 format of your private key. Supported formats are "PEM", "DER", "ENG" and
\&"PROV" (the latter added in curl 8.12.0).

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

This option works only with the following TLS backends:
OpenSSL and wolfSSL
.SH EXAMPLE
.nf
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_SSLKEYTYPE, "PEM");
    curl_easy_setopt(curl, CURLOPT_PROXY_KEYPASSWD, "s3cret");
    result = curl_easy_perform(curl);
    curl_easy_cleanup(curl);
  }
}
.fi
.SH AVAILABILITY
Added in curl 7.52.0
.SH RETURN VALUE
\fIcurl_easy_setopt(3)\fP returns a CURLcode indicating success or error.

CURLE_OK (0) means everything was OK, non\-zero means an error occurred, see
\fIlibcurl\-errors(3)\fP.
.SH SEE ALSO
.BR CURLOPT_PROXY_SSLCERT (3),
.BR CURLOPT_PROXY_SSLKEY (3),
.BR CURLOPT_SSLKEYTYPE (3)