CURLOPT_PROXY_CAPATH(3)

💖 CURLOPT_PROXY_CAPATH(3) 💖

okay bestie, welcome to the CURLOPT_PROXY_CAPATH(3) page from the Library Functions Manual. This one is all about telling libcurl where to find a directory full of CA certs for verifying your HTTPS proxy. Slay. 🫶

✨ NAME ✨

CURLOPT_PROXY_CAPATH — directory holding HTTPS proxy CA certificates.

🦋 SYNOPSIS 🦋

okay so the actual signature is giving:

#include <curl/curl.h>

CURLcode curl_easy_setopt(CURL *handle, CURLOPT_PROXY_CAPATH, char *capath);

💖 DESCRIPTION 💖

Pass a char pointer to a null-terminated string naming a directory holding multiple CA certificates to verify the HTTPS proxy with. iconic. If libcurl is built against OpenSSL, the certificate directory must be prepared using the OpenSSL c_rehash utility. No cap.

This makes sense only when CURLOPT_PROXY_SSL_VERIFYPEER(3) is enabled (which it is by default). So like, keep that in mind, bestie.

The application does not have to keep the string around after setting this option. You can let it go, it's fine. 💅

Using this option multiple times makes the last set string override the previous ones. Set it to NULL to disable its use again and switch back to internal default. The default value for this can be figured out with CURLINFO_CAPATH(3).

🎀 DEFAULT 🎀

NULL

🌈 PROTOCOLS 🌈

This functionality affects all TLS based protocols: HTTPS, FTPS, IMAPS, POP3S, SMTPS etc. — literally all of them, periodt.

This option works only with the following TLS backends: GnuTLS, OpenSSL and mbedTLS.

🍓 EXAMPLE 🍓

okay so here's the code, bestie:

int main(void)
{
  CURL *curl = curl_easy_init();
  if(curl) {
    CURLcode result;
    curl_easy_setopt(curl, CURLOPT_URL, "https://example.com/");
    /* using an HTTPS proxy */
    curl_easy_setopt(curl, CURLOPT_PROXY, "https://proxy.example:443");
    curl_easy_setopt(curl, CURLOPT_PROXY_CAPATH, "/etc/cert-dir");
    result = curl_easy_perform(curl);
    curl_easy_cleanup(curl);
  }
}

⭐ AVAILABILITY ⭐

Added in curl 7.52.0. she's not new new, but she's iconic. 👑

💅 RETURN VALUE 💅

CURLE_OK if supported; or an error such as:

• CURLE_NOT_BUILT_IN - Not supported by the SSL backend
• CURLE_UNKNOWN_OPTION
• CURLE_OUT_OF_MEMORY

🔥 SEE ALSO 🔥

CURLOPT_CAINFO(3), CURLOPT_DEBUGFUNCTION(3), CURLOPT_PROXY_CAINFO(3), CURLOPT_PROXY_SSL_VERIFYHOST(3), CURLOPT_STDERR(3)

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xoxo, this was libcurl 💖 — page dated 2026-10-12 — CURLOPT_PROXY_CAPATH(3), mwah. 🎀