Description

setcookie(
    string $name,
    string $value = "",
    int $expires_or_options = 0,
    string $path = "",
    string $domain = "",
    bool $secure = false,
    bool $httponly = false
): bool

Alternative signature available as of PHP 7.3.0 (not supported with named parameters):

setcookie(string $name, string $value = "", array $options = []): bool

setcookie() defines a cookie to be sent along with the rest of the HTTP headers. Like other headers, cookies must be sent before any output from the script (this is a protocol restriction). This requires that this function is called prior to any output, including <html> and <head> tags as well as any whitespace.

Once the cookies have been set, they can be accessed on the next page load with the $_COOKIE array. Cookie values may also exist in $_REQUEST.

Parameters

» RFC 6265 provides the normative reference on how each setcookie() parameter is interpreted.

name: The name of the cookie.
value: The value of the cookie. This value is stored on the clients computer; do not store sensitive information. Assuming the name is 'cookiename', this value is retrieved through $_COOKIE['cookiename']
expires_or_options: The time the cookie expires. This is a Unix timestamp so is in number of seconds since the epoch. One way to set this is by adding the number of seconds before the cookie should expire to the result of calling time(). For instance, time()+60*60*24*30 will set the cookie to expire in 30 days. Another option is to use the mktime() function. If set to 0, or omitted, the cookie will expire at the end of the session (when the browser closes).
Note: The expires_or_options parameter takes a Unix timestamp, as opposed to the date format Wdy, DD-Mon-YYYY HH:MM:SS GMT, because PHP does this conversion internally.
path: The path on the server in which the cookie will be available on. If set to '/', the cookie will be available within the entire domain. If set to '/foo/', the cookie will only be available within the /foo/ directory and all sub-directories such as /foo/bar/ of domain. The default value is the current directory that the cookie is being set in.
domain: The (sub)domain that the cookie is available to. Setting this to a subdomain (such as 'www.example.com') will make the cookie available to that subdomain and all other sub-domains of it (i.e. w2.www.example.com). To make the cookie available to the whole domain (including all subdomains of it), simply set the value to the domain name ('example.com', in this case). Older browsers still implementing the deprecated » RFC 2109 may require a leading . to match all subdomains.
secure: Indicates that the cookie should only be transmitted over a secure HTTPS connection from the client. When set to true, the cookie will only be set if a secure connection exists. On the server-side, it's on the programmer to send this kind of cookie only on secure connection (e.g. with respect to $_SERVER["HTTPS"]).
httponly: When true the cookie will be made accessible only through the HTTP protocol. This means that the cookie won't be accessible by scripting languages, such as JavaScript. It has been suggested that this setting can effectively help to reduce identity theft through XSS attacks (although it is not supported by all browsers), but that claim is often disputed. true or false
options: An associative array which may have any of the keys expires, path, domain, secure, httponly and samesite. The values have the same meaning as described for the parameters with the same name. The value of the samesite element should be either None, Lax or Strict. If any of the allowed options are not given, their default values are the same as the default values of the explicit parameters. If the samesite element is omitted, no SameSite cookie attribute is set.
Note: To set a cookie that includes attributes that aren't among the keys listed, use header().

Note: If samesite is "None" then secure must also be enabled or the cookie will be blocked by the client.

Return Values

If output exists prior to calling this function, setcookie() will fail and return false. If setcookie() successfully runs, it will return true. This does not indicate whether the user accepted the cookie.

Errors/Exceptions

If the options array contains unsupported keys:

Prior to PHP 8.0.0, an E_WARNING was generated.
As of PHP 8.0.0, a ValueError is thrown.

Changelog

Version	Description
8.2.0	The date format of the cookie is now `'D, d M Y H:i:s \G\M\T'`; previously it was `'D, d-M-Y H:i:s T'`.
8.0.0	Passing unsupported keys now throws a ValueError instead of emitting an `E_WARNING`.
7.3.0	An alternative signature supporting an `options` array has been added. This signature supports also setting of the SameSite cookie attribute.

Examples

The effects of the following examples can be observed using the browser developer tools cookie list (usually in the Storage or Application tab).

Example #1 setcookie() send example

<?php

$value = 'something from somewhere';

// Set a "session cookie" that expires when the browser is closed
setcookie("TestCookie", $value);
// Set a cookie that expires in 1 hour
setcookie("TestCookie", $value, time()+3600);
// Set a cookie that applies only to a specific path on a specific domain
// Note that the domain used should match the site domain
setcookie("TestCookie", $value, time()+3600, "/~rasmus/", "example.com", true);

?>

Note that the value portion of the cookie will automatically be urlencoded and decoded by PHP. This can be avoided by using setrawcookie() instead.

To see the contents of the cookies set in the above example on a later request:

<?php
// Print an individual cookie
echo $_COOKIE["TestCookie"];

// Another way to debug/test is to view all cookies
print_r($_COOKIE);
?>

Example #2 setcookie() delete example

To delete a cookie set the expiration date to a value in the past (but not zero, which is reserved for session cookies).

To delete the cookies set in previous example:

<?php
// set the expiration date to one hour ago
setcookie("TestCookie", "", time() - 3600);
setcookie("TestCookie", "", time() - 3600, "/~rasmus/", "example.com", 1);
?>

Example #3 setcookie() and arrays

An "array of cookies" can be set by using array notation in the cookie name. This has the effect of setting as many cookies as there are array elements, but when the cookie is received by the script, the values are all placed in an array with the cookie's name:

<?php
// set the cookies
setcookie("cookie[three]", "cookiethree");
setcookie("cookie[two]", "cookietwo");
setcookie("cookie[one]", "cookieone");

// after the page reloads, print them out
if (isset($_COOKIE['cookie'])) {
    foreach ($_COOKIE['cookie'] as $name => $value) {
        $name = htmlspecialchars($name);
        $value = htmlspecialchars($value);
        echo "$name : $value <br />\n";
    }
}
?>

The above example will output:

three : cookiethree
two : cookietwo
one : cookieone

Note: Using separator characters such as [ and ] as part of the cookie name is not compliant to RFC 6265, section 4, but supposed to be supported by user agents according to RFC 6265, section 5.

Notes

Note: Output buffering can be used to allow script output prior to the call of this function. All output will be buffered until it is flushed (either explicitly or at the end of the script execution). This is done by calling ob_start() and ob_end_flush() in the script, or setting the output_buffering configuration directive on in the php.ini or server configuration files.

Common Pitfalls:

Cookies will not become visible until the next loading of a page that the cookie should be visible for. To test if a cookie was successfully set, check for the cookie on a next loading page before the cookie expires. Expire time is set via the expires_or_options parameter. A nice way to debug the existence of cookies is by simply calling print_r($_COOKIE);.
Cookies must be deleted with the same parameters as they were set with. If the value argument is an empty string, and all other arguments match a previous call to setcookie(), then the cookie with the specified name will be deleted from the remote client. This is internally achieved by setting value to 'deleted' and expiration time in the past.
Because setting a cookie with a value of false will try to delete the cookie, boolean values should not be used. Instead, use 0 for false and 1 for true.
Cookies names can be set as array names and will be available to the PHP scripts as arrays but separate cookies are stored by the browser. Consider json_encode() to set one cookie with multiple names and values. It is not recommended to use serialize() for this purpose because it can result in security holes.

Multiple calls to setcookie() are performed in the order called.

setcookie