How do you handle email bounce backs?

bigMlittleC used Ask the Experts™
We're building a HTML email newsletter campaign creator, my questions are;

- how do you handle bounce-backs?  What are the standard flags we can search for in the emails being received back? Is it possible to distinguish between permanent and temporary bounces as well as blocked messages?
- Anyone got any tips on beating the spam filters for HTML/Plain text emails?

Thanks in advance.
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Most Valuable Expert 2011
Top Expert 2016
This is a REALLY loaded question and it is the entire basis for the existence of a company called "Constant Contact" (there are competitors including iContact, and others) because they have several full-time employees devoted to the work of answering this question in the ever-changing environment of email, spam filters, HTML-rendering engines, etc.  The central issue you will discover as you work through this morass is that you are assuming responsibility for the behavior of far-off client computers with an unpredictable array of email programs and ever-changing spam filters.

Now having said that, let me try to give you some perspective and guidance.  Via my several managed web sites, I send thousands of broadcast email messages each week and thousands more each month.  Whenever I get a change to make it happen I move a client's application from my scripts to Constant Contact.

Bounce-backs are handled via a thing called a "pipe" that is typically a PHP script running on your server.  It can read and process the bounced email.  You can use specialized headers to cause the bounced messages to go to the email address of your pipe.  Most hosting companies can help you set this up.  Learn more here:

It is possible to differentiate between permanent and temporary bounces.  But codifying this is a never-ending task.  You will have to look at every message and determine from the bounce text what has happened to the message.  The bounce texts are as rich and varied as the combinations and permutations of email servers and email clients.  I would suggest setting up some kind of a Class so you can apply OOP to this issue.

Beating spam filters is what Constant Contact does best.  They are well known to the most popular spam filters and have a rigid, enforced antispam policy.  So their headers in messages have some authoritative value.  If your server adds headers to your messages, you will almost certainly run afoul of some of the spam filters which assume, for better or worse, that automatically generated messages may be spam.  This may be of help as you try to navigate those waters:

You probably also want to learn about this thing:

Best of luck with your project.  It will provide lots of hours of employment and "entertainment" for you!

HTH, ~Ray


The other option is, of course, to use mailchimp or constant contact - anyone got any recommendations on which is better?

We really need it to handle import CSVs with differing fields as well as standard content.


Most Valuable Expert 2011
Top Expert 2016

We tested iContact and Constant Contact - both had free trial periods.  You might want to set up some test cases and wade right into them.  IIRC it was a no-obligation test period with full functionality - just a limited number of email recipients.  Constant Contact was our choice here at the church because it was easier for our communications staff.

Not sure I understand "handle import CSVs with differing fields" but the tech support at either company would be glad to help with that, I am sure.

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