How do you make sure email you send programmatically is not automatically marked as spam?

Solution 1:

Use email authentication methods, such as SPF, and DKIM to prove that your emails and your domain name belong together, and to prevent spoofing of your domain name. The SPF website includes a wizard to generate the DNS information for your site.

Check your reverse DNS to make sure the IP address of your mail server points to the domain name that you use for sending mail.

Make sure that the IP-address that you're using is not on a blacklist

Make sure that the reply-to address is a valid, existing address.

Use the full, real name of the addressee in the To field, not just the email-address (e.g. "John Smith" <[email protected]> ).

Monitor your abuse accounts, such as [email protected] and [email protected]. That means - make sure that these accounts exist, read what's sent to them, and act on complaints.

Finally, make it really easy to unsubscribe. Otherwise, your users will unsubscribe by pressing the spam button, and that will affect your reputation.

That said, getting Hotmail to accept your emails remains a black art.

Solution 2:

Sign up for an account on as many major email providers as possible (gmail/yahoo/hotmail/aol/etc). If you make changes to your emails, either major rewording, changes to the code that sends the emails, changes to your email servers, etc, make sure to send test messages to all your accounts and verify that they are not being marked as spam.

Solution 3:

A few bullet points from a previous answer:

Most important: Does the sender address ("From") belong to a domain that runs on the server you send the E-Mail from? If not, make it so. Never use sender addresses like [email protected]. User reply-to if you need replies to arrive at a different address.
Is your server on a blacklist (e.g. check IP on spamhaus.org)? This is a possibility when you're on shared hosting when neighbours behave badly.
Are mails filtered by a spam filter? Open an account with a freemailer that has a spam folder and find out. Also, try sending mail to an address without any spam filtering at all.
Do you possibly need the fifth parameter "-f" of mail() to add a sender address? (See mail() command in the PHP manual)
If you have access to log files, check those, of course.
Do you check the "from:" address for possible bounce mails ("Returned to sender")? You can also set up a separate "errors-to" address.

Solution 4:

You can tell your users to add your From address to their contacts when they complete their order, which, if they do so, will help a lot.

Otherwise, I would try to get a log from some of your users. Sometimes they have details about why it was flagged as spam in the headers of the message, which you could use to tweak the text.

Other things you can try:

Put your site name or address in the subject
Keep all links in the message pointing to your domain (and not email.com)
Put an address or other contact information in the email

Solution 5:

Confirm that you have the correct email address before sending out emails. If someone gives the wrong email address on sign-up, beat them over the head about it ASAP.

Always include clear "how to unsubscribe" information in EVERY email. Do not require the user to login to unsubscribe, it should be a unique url for 1-click unsubscribe.

This will prevent people from marking your mails as spam because "unsubscribing" is too hard.