.\" generated by cd2nroff 0.1 from CURLOPT_PROXY_CAINFO.md
.TH CURLOPT_PROXY_CAINFO 3 "2025-10-19" libcurl
.SH NAME
CURLOPT_PROXY_CAINFO \- path to proxy Certificate Authority (CA) bundle
.SH SYNOPSIS
.nf
#include <curl/curl.h>

CURLcode curl_easy_setopt(CURL *handle, CURLOPT_PROXY_CAINFO, char *path);
.fi
.SH DESCRIPTION
This option is for connecting to an HTTPS proxy, not an HTTPS server.

Pass a char pointer to a null\-terminated string naming a file holding one or
more certificates to verify the HTTPS proxy with.

If \fICURLOPT_PROXY_SSL_VERIFYPEER(3)\fP is zero and you avoid verifying the
server\(aqs certificate, \fICURLOPT_PROXY_CAINFO(3)\fP need not even indicate an
accessible file.

This option is by default set to the system path where libcurl\(aqs CA
certificate bundle is assumed to be stored, as established at build time.

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 and switches back to
internal default.

The default value for this can be figured out with \fICURLINFO_CAINFO(3)\fP.
.SH DEFAULT
Built\-in system specific
.SH PROTOCOLS
This functionality affects all TLS based protocols: HTTPS, FTPS, IMAPS, POP3S, SMTPS etc.

All TLS backends support this option.
.SH EXAMPLE
.nf
int main(void)
{
  CURL *curl = curl_easy_init();
  if(curl) {
    CURLcode res;
    curl_easy_setopt(curl, CURLOPT_URL, "https://example.com/");
    /* using an HTTPS proxy */
    curl_easy_setopt(curl, CURLOPT_PROXY, "https://localhost:443");
    curl_easy_setopt(curl, CURLOPT_PROXY_CAINFO, "/etc/certs/cabundle.pem");
    res = curl_easy_perform(curl);
    curl_easy_cleanup(curl);
  }
}
.fi
.SH NOTES
For TLS backends that do not support certificate files, the
\fICURLOPT_PROXY_CAINFO(3)\fP option is ignored. Refer to
https://curl.se/docs/ssl\-compared.html
.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_CAINFO (3),
.BR CURLOPT_CAINFO_BLOB (3),
.BR CURLOPT_CAPATH (3),
.BR CURLOPT_PROXY_CAINFO_BLOB (3),
.BR CURLOPT_PROXY_CAPATH (3),
.BR CURLOPT_PROXY_SSL_VERIFYHOST (3),
.BR CURLOPT_PROXY_SSL_VERIFYPEER (3),
.BR CURLOPT_SSL_VERIFYHOST (3),
.BR CURLOPT_SSL_VERIFYPEER (3)