CURLOPT_SSLCERT(3) Library Functions Manual CURLOPT_SSLCERT(3)
NAME
CURLOPT_SSLCERT - SSL client certificate
SYNOPSIS
#include <curl/curl.h>
CURLcode curl_easy_setopt(CURL *handle, CURLOPT_SSLCERT, char *cert);
DESCRIPTION
Pass a pointer to a null-terminated string as parameter. The string
should be the filename of your client certificate. The default format
is PEM but can be changed with CURLOPT_SSLCERTTYPE(3).
(Schannel) Client certificates can be specified by a path expression to
a certificate store. (You can import PFX to a store first). You can use
"<store location>\<store name>\<thumbprint>" to refer to a certificate
in the system certificates store, for example,
"CurrentUser\MY\934a7ac6f8a5d5". The thumbprint is usually a SHA-1 hex
string which you can see in certificate details. Following store
locations are supported: CurrentUser, LocalMachine, CurrentService,
Services, CurrentUserGroupPolicy, LocalMachineGroupPolicy,
LocalMachineEnterprise. Schannel also support P12 certificate file,
with the string P12 specified with CURLOPT_SSLCERTTYPE(3).
When using a client certificate, you most likely also need to provide a
private key with CURLOPT_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.
All TLS backends support this option.
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_SSLKEY, "key.pem");
curl_easy_setopt(curl, CURLOPT_KEYPASSWD, "s3cret");
result = curl_easy_perform(curl);
curl_easy_cleanup(curl);
}
}
AVAILABILITY
Added in curl 7.1
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_KEYPASSWD(3), CURLOPT_SSLCERTTYPE(3), CURLOPT_SSLKEY(3)
libcurl 2026-03-23 CURLOPT_SSLCERT(3)
curl 8.19.0 - Generated Tue Mar 31 13:35:44 CDT 2026