From and reply to: Routability and matching domains?
Here’s a question that comes up enough that I’ve got multiple versions of it sitting in my blog scratchpad, just waiting for me to draft my thoughts. And I've got thoughts! Let me share those thoughts, just after sharing the the two main versions of this question that I've received:
My email from address isn’t routable. But my reply-to is. Is that good enough? Will I have deliverability troubles?
Do my from address and reply-to have to match? What if they’re different domains? Does this negatively impact deliverability?
Let us begin with with: Documented Requirements
Any email addresses in the reply-to or from address need to be at domains with proper working DNS. MX records, A records, SOA records, whatever; you need all of the usual stuff. It needs to exist, it needs to resolve in DNS, it needs to accept mail.
Microsoft, for example, explicitly states that your sender addresses exist and accept mail. They talk about it in the context of P2 sender address compliance. (And here’s my explanation of what that means.) I interpret the “must accept mail” requirement as suggesting that “no reply” addresses are not acceptable. Can they police this well? I’m not sure they can, but to pick that nit misses the point. This is one of those things that will bite you eventually, even if not today.
Can from and reply-to addresses be at different domains?
In a perfect world, it’d be great if the from address and reply-to address were both at the same domain, or at least, were matching subdomains. Sending from email.spamresource.com and using a reply-to of reply.spamresource.com, if you need to route things differently to go into some sort of automation for reply handling. Start there. If you’ve got a way to do that, you’re going to be best off.
Do they HAVE to match, though? No. Spam filters don’t generally care if the from address and reply-to address don’t match. It can still trip you up, though. Here’s a few different ways it can still cause you pain:
If either address is at a free webmail domain. Meaning, don’t send email as Gmail or Yahoo Mail, and don’t set up your reply-to to point at a free webmail address. Why? Short answer: This is a spam sign.
Don’t do anything tricky to try to sneak in a reference to a webmail domain in the email address or in the “friendly from.” Google, in particular, looks for funny stuff that might suggest that an address is trying to look like a Gmail address, but isn’t.
If you have separate from and reply-to addresses; some people are still going to email the from address, instead of the reply-to. There’s no way around it. People will capture the wrong address, either manually, or their webmail platform will helpfully scrape it from the email’s from address and put it in the recipient’s address book. Let me say that again: You WILL get replies at the from address. It will happen. So having one that is non-routable, non-replyable, a “do not reply,” where inbound emails are ignored or rejected, eventually could end up being problematic. Maybe you have no choice, and maybe you’ll do whatever you can to help minimize the pain from this. Handle it however you must, be aware of the risk.
It Boils Down To This
I’ve had to deal with all of these different scenarios, and for the most part, as long as you’re staying away from free/webmail domains, a mismatch between from and reply-to itself isn’t a problem. The non-routability of a from address WILL be a problem; but how much of a problem is going to vary. From addresses going nowhere on low value bulk sends to millions will probably be less of an immediate concern than marketing automations going to small groups of highly engaged customers that you’re hoping to hear back from. If there’s anything involved that is meant to mimic a 1:1 email in any possible way, mail to that from address better lead back to a real person, or you’re going to miss an important reply, because somebody, somewhere, will email the from address instead of the reply-to.
And if you’re building something new, or getting your brand or company set up on an ESP or marketing automation platform anew, make sure all the email addresses work, can receive replies, and those replies get routed somewhere. “No reply” is an outdated configuration in 2026.
Here’s a question that comes up enough that I’ve got multiple versions of it sitting in my blog scratchpad, just waiting for me to draft my thoughts. And I've got thoughts! Let me share those thoughts, just after sharing the the two main versions of this question that I've received:
Let us begin with with: Documented Requirements
Any email addresses in the reply-to or from address need to be at domains with proper working DNS. MX records, A records, SOA records, whatever; you need all of the usual stuff. It needs to exist, it needs to resolve in DNS, it needs to accept mail.Microsoft, for example, explicitly states that your sender addresses exist and accept mail. They talk about it in the context of P2 sender address compliance. (And here’s my explanation of what that means.) I interpret the “must accept mail” requirement as suggesting that “no reply” addresses are not acceptable. Can they police this well? I’m not sure they can, but to pick that nit misses the point. This is one of those things that will bite you eventually, even if not today.
Can from and reply-to addresses be at different domains?
In a perfect world, it’d be great if the from address and reply-to address were both at the same domain, or at least, were matching subdomains. Sending from email.spamresource.com and using a reply-to of reply.spamresource.com, if you need to route things differently to go into some sort of automation for reply handling. Start there. If you’ve got a way to do that, you’re going to be best off.Do they HAVE to match, though? No. Spam filters don’t generally care if the from address and reply-to address don’t match. It can still trip you up, though. Here’s a few different ways it can still cause you pain:
It Boils Down To This
I’ve had to deal with all of these different scenarios, and for the most part, as long as you’re staying away from free/webmail domains, a mismatch between from and reply-to itself isn’t a problem. The non-routability of a from address WILL be a problem; but how much of a problem is going to vary. From addresses going nowhere on low value bulk sends to millions will probably be less of an immediate concern than marketing automations going to small groups of highly engaged customers that you’re hoping to hear back from. If there’s anything involved that is meant to mimic a 1:1 email in any possible way, mail to that from address better lead back to a real person, or you’re going to miss an important reply, because somebody, somewhere, will email the from address instead of the reply-to.And if you’re building something new, or getting your brand or company set up on an ESP or marketing automation platform anew, make sure all the email addresses work, can receive replies, and those replies get routed somewhere. “No reply” is an outdated configuration in 2026.
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