Each line should be separated with a CRLF (\r\n). Lines should not be larger than 70 characters.
(Windows only) When PHP is talking to a SMTP server directly, if a full stop is found on the start of a line, it is removed. To counter-act this, replace these occurrences with a double dot.
String or array to be inserted at the end of the email header.
This is typically used to add extra headers (From, Cc, and Bcc). Multiple extra headers should be separated with a CRLF (\r\n). If outside data are used to compose this header, the data should be sanitized so that no unwanted headers could be injected.
If an array is passed, its keys are the header names and its values are the respective header values.
Note:
Before PHP 5.4.42 and 5.5.27, repectively, additional_headers did not have mail header injection protection. Therefore, users must make sure specified headers are safe and contains headers only. i.e. Never start mail body by putting multiple newlines.
Note:
When sending mail, the mail must contain a From header. This can be set with the additional_headers parameter, or a default can be set in php.ini .
Failing to do this will result in an error message similar to Warning: mail(): «sendmail_from» not set in php.ini or custom «From:» header missing . The From header sets also Return-Path when sending directly via SMTP (Windows only).
Note:
If messages are not received, try using a LF (\n) only. Some Unix mail transfer agents (most notably » qmail) replace LF by CRLF automatically (which leads to doubling CR if CRLF is used). This should be a last resort, as it does not comply with » RFC 2822.
The additional_params parameter can be used to pass additional flags as command line options to the program configured to be used when sending mail, as defined by the sendmail_path configuration setting. For example, this can be used to set the envelope sender address when using sendmail with the -f sendmail option.
This parameter is escaped by escapeshellcmd() internally to prevent command execution. escapeshellcmd() prevents command execution, but allows to add additional parameters. For security reasons, it is recommended for the user to sanitize this parameter to avoid adding unwanted parameters to the shell command.
Since escapeshellcmd() is applied automatically, some characters that are allowed as email addresses by internet RFCs cannot be used. mail() can not allow such characters, so in programs where the use of such characters is required, alternative means of sending emails (such as using a framework or a library) is recommended.
The user that the webserver runs as should be added as a trusted user to the sendmail configuration to prevent a ‘X-Warning’ header from being added to the message when the envelope sender (-f) is set using this method. For sendmail users, this file is /etc/mail/trusted-users .
Return Values
Returns true if the mail was successfully accepted for delivery, false otherwise.
It is important to note that just because the mail was accepted for delivery, it does NOT mean the mail will actually reach the intended destination.
Changelog
| Version | Description |
|---|---|
| 7.2.0 | The additional_headers parameter now also accepts an array . |
Examples
Example #1 Sending mail.
Using mail() to send a simple email:
// The message
$message = «Line 1\r\nLine 2\r\nLine 3» ;
// In case any of our lines are larger than 70 characters, we should use wordwrap()
$message = wordwrap ( $message , 70 , «\r\n» );
// Send
mail ( ‘caffeinated@example.com’ , ‘My Subject’ , $message );
?>
Example #2 Sending mail with extra headers.
The addition of basic headers, telling the MUA the From and Reply-To addresses:
$to = ‘nobody@example.com’ ;
$subject = ‘the subject’ ;
$message = ‘hello’ ;
$headers = ‘From: webmaster@example.com’ . «\r\n» .
‘Reply-To: webmaster@example.com’ . «\r\n» .
‘X-Mailer: PHP/’ . phpversion ();
mail ( $to , $subject , $message , $headers );
?>
Example #3 Sending mail with extra headers as array
This example sends the same mail as the example immediately above, but passes the additional headers as array (available as of PHP 7.2.0).
$to = ‘nobody@example.com’ ;
$subject = ‘the subject’ ;
$message = ‘hello’ ;
$headers = array(
‘From’ => ‘webmaster@example.com’ ,
‘Reply-To’ => ‘webmaster@example.com’ ,
‘X-Mailer’ => ‘PHP/’ . phpversion ()
);
mail ( $to , $subject , $message , $headers );
?>
Example #4 Sending mail with an additional command line parameter.
The additional_params parameter can be used to pass an additional parameter to the program configured to use when sending mail using the sendmail_path .
Example #5 Sending HTML email
It is also possible to send HTML email with mail() .
// Multiple recipients
$to = ‘johny@example.com, sally@example.com’ ; // note the comma
// Subject
$subject = ‘Birthday Reminders for August’ ;
// Message
$message = ‘
Here are the birthdays upcoming in August!
| Person | Day | Month | Year |
|---|---|---|---|
| Johny | 10th | August | 1970 |
| Sally | 17th | August | 1973 |
‘ ;
// To send HTML mail, the Content-type header must be set
$headers [] = ‘MIME-Version: 1.0’ ;
$headers [] = ‘Content-type: text/html; charset=iso-8859-1’ ;
// Additional headers
$headers [] = ‘To: Mary , Kelly ‘ ;
$headers [] = ‘From: Birthday Reminder ‘ ;
$headers [] = ‘Cc: birthdayarchive@example.com’ ;
$headers [] = ‘Bcc: birthdaycheck@example.com’ ;
// Mail it
mail ( $to , $subject , $message , implode ( «\r\n» , $headers ));
?>
Note:
If intending to send HTML or otherwise Complex mails, it is recommended to use the PEAR package » PEAR::Mail_Mime.
Notes
Note:
The SMTP implementation (Windows only) of mail() differs in many ways from the sendmail implementation. First, it doesn’t use a local binary for composing messages but only operates on direct sockets which means a MTA is needed listening on a network socket (which can either on the localhost or a remote machine).
Second, the custom headers like From: , Cc: , Bcc: and Date: are not interpreted by the MTA in the first place, but are parsed by PHP.
As such, the to parameter should not be an address in the form of «Something «. The mail command may not parse this properly while talking with the MTA.
Note:
It is worth noting that the mail() function is not suitable for larger volumes of email in a loop. This function opens and closes an SMTP socket for each email, which is not very efficient.
For the sending of large amounts of email, see the » PEAR::Mail, and » PEAR::Mail_Queue packages.
See Also
How to send Emails in PHP?
PHP is one of the most popular web-development languages and a popular way to create dynamic web apps. In this article we’re going to help you painlessly configure the mail function in your application. So let us start! There are two basic ways of sending emails with PHP: a built-in mail function and external mail packages. To read the full article, check out Mailtrap’s blog: How to Send Emails in PHP?
PHP built-in mail function ()
- create simple HTML/text messages without attachments and images
- send emails via localhost and Xmapp
- include several recipients with “$to” parameter.
It is suitable for simple, mostly text-based notifications in your local environment. If you need to communicate with your app’s users, it is better to install an external mailer package.
If you are still committed to the PHP built-in mail function() and are ready to accept the challenge, let’s take a look at the basic code and its main parameters.
Syntax and parameters
The PHP mail syntax is pretty simple:
It uses the following parameters:
- “$to” = your message recipient(s). The email address format may be user@example.com or User user@example.com. In general, it needs to comply with RFC 2822.
- “$subject” = your message’s subject
- “$message” = the body of your message. Lines should be separated with a CRLF (\r\n). Each line should not exceed 70 characters.
- “[$headers]” = additional recipients of your message, which can be included in CC or BCC.
Note that headers are optional, except for the “from” header: it must be specified, otherwise, you will receive an error message like Warning: mail(): “sendmail_from” not set in php.ini or custom “From:” header missing.
You can use additional headers to change the mail “From” address and set the “Reply to” address.
For more details and additional parameters, refer to the PHP documentation.
Sending HTML email using PHP mail() function
The body of the message can be written in HTML. However, as we’ve mentioned above, it should be simple. In the PHP mail function(), the HTML part will look like this:
$message = ' Here are the cases requiring your review in December:
Case title Category Status Due date Case 1 Development pending Dec-20 Case 1 DevOps pending Dec-21
'; It’s important to remember that to send HTML mail, you need to set the Content-type header:
$headers[] = ‘MIME-Version: 1.0’;
$headers[] = ‘Content-type: text/html; charset=iso-8859-1’;
Simple Transmission Protocol (SMTP)
Where do I specify the SMTP settings? This is a fair question. Go to the PHP installation folder and configure them in the “php.ini” file. But this will only work for localhost or Xmapp like solutions because as we have already mentioned, PHP mail function does not support SMTP authentication and doesn’t allow sending messages via external servers.
There are some other, rather haphazard options but we won’t promote them here. Alternatively, we recommend using external PHP mail packages for sending emails via an external SMTP server.
PHP mailing packages
As we have already mentioned, the native PHP mail() function has limited functionality when it comes to mass sending. For example, it is not designed for creating engaging email templates that may boost your next campaign or sending a large volume of emails.
But since PHP is still one of the most popular programming languages, it also doesn’t lack resources for sending mass emails. We can highly recommend several plugins, such as Pear Mail and Swift Mailer
Pear Mail is a class that provides multiple interfaces for sending emails (which is stated in their documentation).
Here is what you can do with Pear Mail:
- create complex HTML/text messages with attachments and inlined images (with Mail_Mime class)
- send emails via PHP’s built-in mail() function, a sendmail program, or SMTP server
- send multiple emails from a queue (with Mail_Queue class).
Swift Mailer
Swift Mailer is another popular package for sending emails in PHP. It is feature-rich, well covered by documentation, and pretty straightforward in use.
Here is what you can do with Swift Mailer:
- create complex HTML/multipart templates
- add attachments and embed images
- send emails via authenticated SMTP, sendmail, Postfix, or your own transport
- use additional plugins.
Besides that, Swift Mailer offers enhanced security and handles large attachments and images with low memory usage.
And finally, PHPMailer, which is the classic and the most popular email sending library for PHP. It deserves a separate article and a tutorial. You will find it here.
Here is what you can do with PHPMailer:
- create complex HTML/multipart templates
- add attachments and embedded images
- send emails via authenticated SMTP.
PHPMailer is protected against header injection attacks and automatically validates emails.
In this article, we have described the basic PHP email sending principles, syntax, and parameters. Moreover, we have reviewed the main ways of sending emails with PHP: its built-in mail function and the most popular external mail packages. PHPMailer and Swift Mailer are standard libraries for PHP email sending today, and PEAR Mail is still widely used.
Choose your option according to your current needs and preferences and test your emails beforehand. For email experiments — create an account at Mailtrap, a fake SMTP server. It imitates a real SMTP server and traps your test email in the virtual inboxes. Have a try!
Check the full Sending emails with PHP article at Mailtrap.io to get more details on email packages and examples!