I understand that VERP allows you to encode the recipient's email address into the sending email address and we can use this to identify the recipient in bounce management system.

But if I instead want to use a unique identifier to identify a specific message rather than an email address which I may have sent multiple messages to is there anything wrong with me using a from address of something like [email protected] (where 123456789 is my unique message identifier)?

Does using the VERP method offer any other benefits (for example, do mail servers do something differently if the VERP method is used)?

If I send bulk messages (tens of thousands or more) will receiving mail servers have a problem with a unique from address?

I also plan to set the reply-to address to [email protected] so I can treat human replies differently. Is there likely to be any problems with this? I understand that technically some receiving mail servers may send bounces to the reply-to address, but is this likely to happen in the real world? And are any human replies likely to go to the from (bounce) address if a reply-to is present?

Presumably auto responders will go to the reply-to address too?

  • I don't think they will have any problems with unique from addresses, on the contrary isnt that standard? You can only have one from address but multiple receivers. I would try different configs and send myself emails to different clients (outlook, thunderbird, gmail etc) with different methods and then reply etc and figure it out by good old testing.
    – Don King
    Commented Jan 3, 2019 at 15:42

1 Answer 1


From the testing I have done from my end, I generally have the following results:

  • Bounce backs always comeback to the "from" email if a "reply-to" is not configured.
  • Human responses always comeback to the "reply-to" address unless the user chooses to reply to the "original-sender"


  1. Receiving bounceback emails always depend on your configuration.
  2. All major ESPs honor the "reply-to" to send back replies

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