wp_mail( string|string[] $to, string $subject, string $message, string|string[] $headers = '', string|string[] $attachments = array() )

Sends an email, similar to PHP’s mail function.

Description

A true return value does not automatically mean that the user received the email successfully. It just only means that the method used was able to process the request without any errors.

The default content type is text/plain which does not allow using HTML. However, you can set the content type of the email by using the ‘wp_mail_content_type’ filter.

The default charset is based on the charset used on the blog. The charset can be set using the ‘wp_mail_charset’ filter.

Parameters

$to

(string|string[]) (Required) Array or comma-separated list of email addresses to send message.

$subject

(string) (Required) Email subject.

$message

(string) (Required) Message contents.

$headers

(string|string[]) (Optional) Additional headers.

Default value: ''

$attachments

(string|string[]) (Optional) Paths to files to attach.

Default value: array()

Return

(bool) Whether the email was sent successfully.

More Information

Usage 

wp_mail( $to, $subject, $message, $headers, $attachments );

Optional filters ‘wp_mail_from‘ and ‘wp_mail_from_name‘ are run on the sender email address and name. The return values are reassembled into a ‘from’ address like ‘”Example User” ‘ If only ‘wp_mail_from‘ returns a value, then just the email address will be used with no name.

The default content type is ‘text/plain’ which does not allow using HTML. You can set the content type of the email either by using the ‘wp_mail_content_type‘ filter ( see example below), or by including a header like “Content-type: text/html”. Be careful to reset ‘wp_mail_content_type’ back to ‘text/plain’ after you send your message, though, because failing to do so could lead to unexpected problems with e-mails from WP or plugins/themes.

The default charset is based on the charset used on the blog. The charset can be set using the ‘wp_mail_charset‘ filter.

Notes

  • A true return value does not automatically mean that the user received the email successfully.
  • For this function to work, the settings SMTP and smtp_port (default: 25) need to be set in your php.ini file.
  • The function is available after the hook 'plugins_loaded'.
  • The filenames in the $attachments attribute have to be filesystem paths.

Valid Address Formats

All email addresses supplied to wp_mail() as the $to parameter must comply with RFC 2822. Some valid examples:

The same applies to Cc: and Bcc: fields in $headers, but as noted in the next section, it’s better to push multiple addresses into an array instead of listing them on a single line. Either address format, with or without the user name, may be used.

Using $headers To Set “From:”, “Cc:” and “Bcc:” Parameters

To set the “From:” email address to something other than the WordPress default sender, or to add “Cc:” and/or “Bcc:” recipients, you must use the $headers argument.

$headers can be a string or an array, but it may be easiest to use in the array form. To use it, push a string onto the array, starting with “From:”, “Bcc:” or “Cc:” (note the use of the “:”), followed by a valid email address.

When you are using the array form, you do not need to supply line breaks ("\n" or "\r\n"). Although the function can handle multiple emails per line, it may simply be easier to push each email address separately onto the $headers array. The function will figure it out and will build the proper Mime header automagically. Just don’t forget that each string you push must have the header type as the first part of the string (“From:”, “Cc:” or “Bcc:”)

Source

File: wp-includes/pluggable.php 

function wp_mail( $to, $subject, $message, $headers = '', $attachments = array() ) {
		// Compact the input, apply the filters, and extract them back out.

		/**
		 * Filters the wp_mail() arguments.
		 *
		 * @since 2.2.0
		 *
		 * @param array $args {
		 *     Array of the `wp_mail()` arguments.
		 *
		 *     @type string|string[] $to          Array or comma-separated list of email addresses to send message.
		 *     @type string          $subject     Email subject.
		 *     @type string          $message     Message contents.
		 *     @type string|string[] $headers     Additional headers.
		 *     @type string|string[] $attachments Paths to files to attach.
		 * }
		 */
		$atts = apply_filters( 'wp_mail', compact( 'to', 'subject', 'message', 'headers', 'attachments' ) );

		/**
		 * Filters whether to preempt sending an email.
		 *
		 * Returning a non-null value will short-circuit {@see wp_mail()}, returning
		 * that value instead. A boolean return value should be used to indicate whether
		 * the email was successfully sent.
		 *
		 * @since 5.7.0
		 *
		 * @param null|bool $return Short-circuit return value.
		 * @param array     $atts {
		 *     Array of the `wp_mail()` arguments.
		 *
		 *     @type string|string[] $to          Array or comma-separated list of email addresses to send message.
		 *     @type string          $subject     Email subject.
		 *     @type string          $message     Message contents.
		 *     @type string|string[] $headers     Additional headers.
		 *     @type string|string[] $attachments Paths to files to attach.
		 * }
		 */
		$pre_wp_mail = apply_filters( 'pre_wp_mail', null, $atts );

		if ( null !== $pre_wp_mail ) {
			return $pre_wp_mail;
		}

		if ( isset( $atts['to'] ) ) {
			$to = $atts['to'];
		}

		if ( ! is_array( $to ) ) {
			$to = explode( ',', $to );
		}

		if ( isset( $atts['subject'] ) ) {
			$subject = $atts['subject'];
		}

		if ( isset( $atts['message'] ) ) {
			$message = $atts['message'];
		}

		if ( isset( $atts['headers'] ) ) {
			$headers = $atts['headers'];
		}

		if ( isset( $atts['attachments'] ) ) {
			$attachments = $atts['attachments'];
		}

		if ( ! is_array( $attachments ) ) {
			$attachments = explode( "\n", str_replace( "\r\n", "\n", $attachments ) );
		}
		global $phpmailer;

		// (Re)create it, if it's gone missing.
		if ( ! ( $phpmailer instanceof PHPMailer\PHPMailer\PHPMailer ) ) {
			require_once ABSPATH . WPINC . '/PHPMailer/PHPMailer.php';
			require_once ABSPATH . WPINC . '/PHPMailer/SMTP.php';
			require_once ABSPATH . WPINC . '/PHPMailer/Exception.php';
			$phpmailer = new PHPMailer\PHPMailer\PHPMailer( true );

			$phpmailer::$validator = static function ( $email ) {
				return (bool) is_email( $email );
			};
		}

		// Headers.
		$cc       = array();
		$bcc      = array();
		$reply_to = array();

		if ( empty( $headers ) ) {
			$headers = array();
		} else {
			if ( ! is_array( $headers ) ) {
				// Explode the headers out, so this function can take
				// both string headers and an array of headers.
				$tempheaders = explode( "\n", str_replace( "\r\n", "\n", $headers ) );
			} else {
				$tempheaders = $headers;
			}
			$headers = array();

			// If it's actually got contents.
			if ( ! empty( $tempheaders ) ) {
				// Iterate through the raw headers.
				foreach ( (array) $tempheaders as $header ) {
					if ( strpos( $header, ':' ) === false ) {
						if ( false !== stripos( $header, 'boundary=' ) ) {
							$parts    = preg_split( '/boundary=/i', trim( $header ) );
							$boundary = trim( str_replace( array( "'", '"' ), '', $parts[1] ) );
						}
						continue;
					}
					// Explode them out.
					list( $name, $content ) = explode( ':', trim( $header ), 2 );

					// Cleanup crew.
					$name    = trim( $name );
					$content = trim( $content );

					switch ( strtolower( $name ) ) {
						// Mainly for legacy -- process a "From:" header if it's there.
						case 'from':
							$bracket_pos = strpos( $content, '<' );
							if ( false !== $bracket_pos ) {
								// Text before the bracketed email is the "From" name.
								if ( $bracket_pos > 0 ) {
									$from_name = substr( $content, 0, $bracket_pos - 1 );
									$from_name = str_replace( '"', '', $from_name );
									$from_name = trim( $from_name );
								}

								$from_email = substr( $content, $bracket_pos + 1 );
								$from_email = str_replace( '>', '', $from_email );
								$from_email = trim( $from_email );

								// Avoid setting an empty $from_email.
							} elseif ( '' !== trim( $content ) ) {
								$from_email = trim( $content );
							}
							break;
						case 'content-type':
							if ( strpos( $content, ';' ) !== false ) {
								list( $type, $charset_content ) = explode( ';', $content );
								$content_type                   = trim( $type );
								if ( false !== stripos( $charset_content, 'charset=' ) ) {
									$charset = trim( str_replace( array( 'charset=', '"' ), '', $charset_content ) );
								} elseif ( false !== stripos( $charset_content, 'boundary=' ) ) {
									$boundary = trim( str_replace( array( 'BOUNDARY=', 'boundary=', '"' ), '', $charset_content ) );
									$charset  = '';
								}

								// Avoid setting an empty $content_type.
							} elseif ( '' !== trim( $content ) ) {
								$content_type = trim( $content );
							}
							break;
						case 'cc':
							$cc = array_merge( (array) $cc, explode( ',', $content ) );
							break;
						case 'bcc':
							$bcc = array_merge( (array) $bcc, explode( ',', $content ) );
							break;
						case 'reply-to':
							$reply_to = array_merge( (array) $reply_to, explode( ',', $content ) );
							break;
						default:
							// Add it to our grand headers array.
							$headers[ trim( $name ) ] = trim( $content );
							break;
					}
				}
			}
		}

		// Empty out the values that may be set.
		$phpmailer->clearAllRecipients();
		$phpmailer->clearAttachments();
		$phpmailer->clearCustomHeaders();
		$phpmailer->clearReplyTos();

		// Set "From" name and email.

		// If we don't have a name from the input headers.
		if ( ! isset( $from_name ) ) {
			$from_name = 'WordPress';
		}

		/*
		 * If we don't have an email from the input headers, default to wordpress@$sitename
		 * Some hosts will block outgoing mail from this address if it doesn't exist,
		 * but there's no easy alternative. Defaulting to admin_email might appear to be
		 * another option, but some hosts may refuse to relay mail from an unknown domain.
		 * See https://core.trac.wordpress.org/ticket/5007.
		 */
		if ( ! isset( $from_email ) ) {
			// Get the site domain and get rid of www.
			$sitename = wp_parse_url( network_home_url(), PHP_URL_HOST );
			if ( 'www.' === substr( $sitename, 0, 4 ) ) {
				$sitename = substr( $sitename, 4 );
			}

			$from_email = 'wordpress@' . $sitename;
		}

		/**
		 * Filters the email address to send from.
		 *
		 * @since 2.2.0
		 *
		 * @param string $from_email Email address to send from.
		 */
		$from_email = apply_filters( 'wp_mail_from', $from_email );

		/**
		 * Filters the name to associate with the "from" email address.
		 *
		 * @since 2.3.0
		 *
		 * @param string $from_name Name associated with the "from" email address.
		 */
		$from_name = apply_filters( 'wp_mail_from_name', $from_name );

		try {
			$phpmailer->setFrom( $from_email, $from_name, false );
		} catch ( PHPMailer\PHPMailer\Exception $e ) {
			$mail_error_data                             = compact( 'to', 'subject', 'message', 'headers', 'attachments' );
			$mail_error_data['phpmailer_exception_code'] = $e->getCode();

			/** This filter is documented in wp-includes/pluggable.php */
			do_action( 'wp_mail_failed', new WP_Error( 'wp_mail_failed', $e->getMessage(), $mail_error_data ) );

			return false;
		}

		// Set mail's subject and body.
		$phpmailer->Subject = $subject;
		$phpmailer->Body    = $message;

		// Set destination addresses, using appropriate methods for handling addresses.
		$address_headers = compact( 'to', 'cc', 'bcc', 'reply_to' );

		foreach ( $address_headers as $address_header => $addresses ) {
			if ( empty( $addresses ) ) {
				continue;
			}

			foreach ( (array) $addresses as $address ) {
				try {
					// Break $recipient into name and address parts if in the format "Foo <[email protected]>".
					$recipient_name = '';

					if ( preg_match( '/(.*)<(.+)>/', $address, $matches ) ) {
						if ( count( $matches ) == 3 ) {
							$recipient_name = $matches[1];
							$address        = $matches[2];
						}
					}

					switch ( $address_header ) {
						case 'to':
							$phpmailer->addAddress( $address, $recipient_name );
							break;
						case 'cc':
							$phpmailer->addCc( $address, $recipient_name );
							break;
						case 'bcc':
							$phpmailer->addBcc( $address, $recipient_name );
							break;
						case 'reply_to':
							$phpmailer->addReplyTo( $address, $recipient_name );
							break;
					}
				} catch ( PHPMailer\PHPMailer\Exception $e ) {
					continue;
				}
			}
		}

		// Set to use PHP's mail().
		$phpmailer->isMail();

		// Set Content-Type and charset.

		// If we don't have a content-type from the input headers.
		if ( ! isset( $content_type ) ) {
			$content_type = 'text/plain';
		}

		/**
		 * Filters the wp_mail() content type.
		 *
		 * @since 2.3.0
		 *
		 * @param string $content_type Default wp_mail() content type.
		 */
		$content_type = apply_filters( 'wp_mail_content_type', $content_type );

		$phpmailer->ContentType = $content_type;

		// Set whether it's plaintext, depending on $content_type.
		if ( 'text/html' === $content_type ) {
			$phpmailer->isHTML( true );
		}

		// If we don't have a charset from the input headers.
		if ( ! isset( $charset ) ) {
			$charset = get_bloginfo( 'charset' );
		}

		/**
		 * Filters the default wp_mail() charset.
		 *
		 * @since 2.3.0
		 *
		 * @param string $charset Default email charset.
		 */
		$phpmailer->CharSet = apply_filters( 'wp_mail_charset', $charset );

		// Set custom headers.
		if ( ! empty( $headers ) ) {
			foreach ( (array) $headers as $name => $content ) {
				// Only add custom headers not added automatically by PHPMailer.
				if ( ! in_array( $name, array( 'MIME-Version', 'X-Mailer' ), true ) ) {
					try {
						$phpmailer->addCustomHeader( sprintf( '%1$s: %2$s', $name, $content ) );
					} catch ( PHPMailer\PHPMailer\Exception $e ) {
						continue;
					}
				}
			}

			if ( false !== stripos( $content_type, 'multipart' ) && ! empty( $boundary ) ) {
				$phpmailer->addCustomHeader( sprintf( 'Content-Type: %s; boundary="%s"', $content_type, $boundary ) );
			}
		}

		if ( ! empty( $attachments ) ) {
			foreach ( $attachments as $attachment ) {
				try {
					$phpmailer->addAttachment( $attachment );
				} catch ( PHPMailer\PHPMailer\Exception $e ) {
					continue;
				}
			}
		}

		/**
		 * Fires after PHPMailer is initialized.
		 *
		 * @since 2.2.0
		 *
		 * @param PHPMailer $phpmailer The PHPMailer instance (passed by reference).
		 */
		do_action_ref_array( 'phpmailer_init', array( &$phpmailer ) );

		// Send!
		try {
			return $phpmailer->send();
		} catch ( PHPMailer\PHPMailer\Exception $e ) {

			$mail_error_data                             = compact( 'to', 'subject', 'message', 'headers', 'attachments' );
			$mail_error_data['phpmailer_exception_code'] = $e->getCode();

			/**
			 * Fires after a PHPMailer\PHPMailer\Exception is caught.
			 *
			 * @since 4.4.0
			 *
			 * @param WP_Error $error A WP_Error object with the PHPMailer\PHPMailer\Exception message, and an array
			 *                        containing the mail recipient, subject, message, headers, and attachments.
			 */
			do_action( 'wp_mail_failed', new WP_Error( 'wp_mail_failed', $e->getMessage(), $mail_error_data ) );

			return false;
		}
	}

Uses

Uses Description
wp-includes/pluggable.php: pre_wp_mail

Filters whether to preempt sending an email.
wp-includes/class-pop3.php: stripos()
wp-includes/http.php: wp_parse_url()

A wrapper for PHP’s parse_url() function that handles consistency in the return values across PHP versions.
wp-includes/pluggable.php: wp_mail_failed

Fires after a PHPMailer\PHPMailer\Exception is caught.
wp-includes/formatting.php: is_email()

Verifies that an email is valid.
wp-includes/pluggable.php: wp_mail

Filters the wp_mail() arguments.
wp-includes/pluggable.php: wp_mail_from

Filters the email address to send from.
wp-includes/pluggable.php: wp_mail_from_name

Filters the name to associate with the “from” email address.
wp-includes/pluggable.php: wp_mail_content_type

Filters the wp_mail() content type.
wp-includes/pluggable.php: wp_mail_charset

Filters the default wp_mail() charset.
wp-includes/pluggable.php: phpmailer_init

Fires after PHPMailer is initialized.
wp-includes/general-template.php: get_bloginfo()

Retrieves information about the current site.
wp-includes/link-template.php: network_home_url()

Retrieves the home URL for the current network.
wp-includes/plugin.php: apply_filters()

Calls the callback functions that have been added to a filter hook.
wp-includes/plugin.php: do_action()

Calls the callback functions that have been added to an action hook.
wp-includes/plugin.php: do_action_ref_array()

Calls the callback functions that have been added to an action hook, specifying arguments in an array.
wp-includes/class-wp-error.php: WP_Error::__construct()

Initializes the error.

Used By

Used By Description
wp-includes/ms-functions.php: wpmu_new_site_admin_notification()

Notifies the Multisite network administrator that a new site was created.
wp-admin/includes/class-wp-automatic-updater.php: WP_Automatic_Updater::send_plugin_theme_email()

Sends an email upon the completion or failure of a plugin or theme background update.
wp-includes/class-wp-recovery-mode-email-service.php: WP_Recovery_Mode_Email_Service::send_recovery_mode_email()

Sends the Recovery Mode email to the site admin email address.
wp-includes/user.php: _wp_privacy_send_request_confirmation_notification()

Notify the site administrator via email when a request is confirmed.
wp-includes/user.php: _wp_privacy_send_erasure_fulfillment_notification()

Notify the user when their erasure request is fulfilled.
wp-includes/user.php: wp_send_user_request()

Send a confirmation request email to confirm an action.
wp-admin/includes/privacy-tools.php: wp_privacy_send_personal_data_export_email()

Send an email to the user with a link to the personal data export file
wp-includes/functions.php: wp_site_admin_email_change_notification()

Send an email to the old site admin email address when the site admin email address changes.
wp-includes/ms-functions.php: update_network_option_new_admin_email()

Send a confirmation request email when a change of network admin email address is attempted.
wp-includes/ms-functions.php: wp_network_admin_email_change_notification()

Send an email to the old network admin email address when the network admin email address changes.
wp-includes/user.php: retrieve_password()

Handles sending a password retrieval email to a user.
wp-admin/includes/class-wp-automatic-updater.php: WP_Automatic_Updater::send_email()

Sends an email upon the completion or failure of a background core update.
wp-admin/includes/class-wp-automatic-updater.php: WP_Automatic_Updater::send_debug_email()

Prepares and sends an email of a full log of background update results, useful for debugging and geekery.
wp-admin/includes/misc.php: update_option_new_admin_email()

Send a confirmation request email when a change of site admin email address is attempted.
wp-includes/user.php: send_confirmation_on_profile_email()

Send a confirmation request email when a change of user email address is attempted.
wp-admin/includes/upgrade.php: wp_new_blog_notification()

Notifies the site admin that the installation of WordPress is complete.
wp-includes/pluggable.php: wp_password_change_notification()

Notify the blog admin of a user changing password, normally via email.
wp-includes/pluggable.php: wp_new_user_notification()

Email login credentials to a newly-registered user.
wp-includes/pluggable.php: wp_notify_postauthor()

Notify an author (and/or others) of a comment/trackback/pingback on a post.
wp-includes/pluggable.php: wp_notify_moderator()

Notifies the moderator of the site about a new comment that is awaiting approval.
wp-includes/user.php: wp_update_user()

Update a user in the database.
wp-includes/ms-functions.php: wpmu_welcome_user_notification()

Notify a user that their account activation has been successful.
wp-includes/ms-functions.php: newblog_notify_siteadmin()

Notifies the network admin that a new site has been activated.
wp-includes/ms-functions.php: newuser_notify_siteadmin()

Notifies the network admin that a new user has been activated.
wp-includes/ms-functions.php: wpmu_welcome_notification()

Notifies the site administrator that their site activation was successful.
wp-includes/ms-functions.php: wpmu_signup_blog_notification()

Send a confirmation request email to a user when they sign up for a new site. The new site will not become active until the confirmation link is clicked.
wp-includes/ms-functions.php: wpmu_signup_user_notification()

Send a confirmation request email to a user when they sign up for a new user account (without signing up for a site at the same time). The user account will not become active until the confirmation link is clicked.

Changelog

Version Description
5.5.0 is_email() is used for email validation, instead of PHPMailer's default validator.
1.2.1 Introduced.

© 2003–2021 WordPress Foundation
Licensed under the GNU GPLv2+ License.
https://developer.wordpress.org/reference/functions/wp_mail