CURLOPT_SSLCERTTYPE(3) Introduction to Library Functions

NAME

CURLOPT_SSLCERTTYPE - type of client SSL certificate

SYNOPSIS

#include <curl/curl.h>

CURLcode curl_easy_setopt(CURL *handle, CURLOPT_SSLCERTTYPE, char *type);

DESCRIPTION

Pass a pointer to a null-terminated string as parameter. The string
should be the format of your certificate.

Supported formats are "PEM" and "DER", except with Schannel. OpenSSL
and Schannel support "P12" for PKCS#12-encoded files. GnuTLS supports
P12 starting with curl 8.11.0.

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 restores back to internal default.

DEFAULT

"PEM"

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, 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_SSLCERT, "client.pem");
curl_easy_setopt(curl, CURLOPT_SSLCERTTYPE, "PEM");
curl_easy_setopt(curl, CURLOPT_SSLKEY, "key.pem");
curl_easy_setopt(curl, CURLOPT_KEYPASSWD, "s3cret");
result = curl_easy_perform(curl);
curl_easy_cleanup(curl);
}
}

AVAILABILITY

Added in curl 7.9.3

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_SSLCERT(3), CURLOPT_SSLKEY(3)

libcurl 2026-01-08 CURLOPT_SSLCERTTYPE(3)