CURLOPT_COOKIEFILE(3)

okay bestie, this is the glow-up of CURLOPT_COOKIEFILE(3) from the Library Functions Manual, and it's literally all about handing libcurl a cookie file to snack on. 🍪✨

🌸 NAME 🌸

CURLOPT_COOKIEFILE — filename to read cookies from. iykyk. 💅

✨ SYNOPSIS ✨

#include <curl/curl.h>

CURLcode curl_easy_setopt(CURL *handle, CURLOPT_COOKIEFILE, char *filename);

💖 DESCRIPTION 💖

Pass a pointer to a null-terminated string as parameter, bestie. It should point to the filename of your file holding cookie data to read. The cookie data can be in either the old Netscape / Mozilla cookie data format or just regular HTTP headers (Set-Cookie style) dumped to a file. Both are valid; pick your fave. 🫶

It also enables the cookie engine, making libcurl parse and send cookies on subsequent requests with this handle. Cookie engine = on. ✨

By passing the empty string ("") to this option, you enable the cookie engine without reading any initial cookies. And if you tell libcurl the filename is - (just a single minus sign), libcurl instead reads from stdin. iconic stdin behavior, ngl.

Heads up: this option only reads cookies. To make libcurl write cookies to file, see CURLOPT_COOKIEJAR(3). Different option, different vibe.

If you read cookies from a plain HTTP headers file and it does not specify a domain in the Set-Cookie line, then the cookie is not sent since the cookie domain cannot match the target URL's. To address this, set a domain in Set-Cookie line (doing that includes subdomains) or preferably: use the Netscape format. Do that. 💅

The application does not have to keep the string around after setting this option. So you can let it go after the call — no strings attached, literally. 🎀

If you use this option multiple times, you add more files to read cookies from. Setting this option to NULL disables the cookie engine and clears the list of files to read cookies from. Full reset energy. 🔥

The cookies are loaded from the specified file(s) when the transfer starts, not when this option is set. So not at set-option o'clock — at transfer o'clock. ⏰

🚨 SECURITY CONCERNS 🚨

This document previously mentioned how specifying a non-existing file can also enable the cookie engine. While true, we strongly advise against using that method as it is too hard to be sure that files that stay that way in the long run. So yes, it technically can work, but pls don't make that your whole personality. 🙈

🎀 DEFAULT 🎀

NULL

🌈 PROTOCOLS 🌈

This functionality affects http only.

🔥 EXAMPLE 🔥

int main(void)
{
  CURL *curl = curl_easy_init();
  if(curl) {
    CURLcode result;
    curl_easy_setopt(curl, CURLOPT_URL, "https://example.com/foo.bin");

    /* get cookies from an existing file */
    curl_easy_setopt(curl, CURLOPT_COOKIEFILE, "/tmp/cookies.txt");

    result = curl_easy_perform(curl);

    curl_easy_cleanup(curl);
  }
}

🍪 Cookie file format 🍪

The cookie file format and general cookie concepts in curl are described online here: https://curl.se/docs/http-cookies.html

⭐ 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_COOKIE(3)
• CURLOPT_COOKIEJAR(3)
• CURLOPT_COOKIESESSION(3)

mwah 💋 — with love from the libcurl girlies, source: libcurl, date: 2026-10-12, page: CURLOPT_COOKIEFILE(3). periodt. 🎀