I'm trying to use Postmark App service (https://postmarkapp.com) to forward email to my subdomain to my PostmarkApp server. I'm trying to use inbound domain forwarding by configuring my MX record to point to my Postmark email server. The Postmark docs mentions to give the MX record a value of 10 (which i did) and to post to an inbound domain you will create at Postmark.

The problem i have is creating a valid domain at PostmarkApp... Specifically, the docs mention: "In your DNS configuration, create an MX record that points to inbound.postmarkapp.com and give it a value of 10" Where inbound is this example is the name of the server they have created inside PostmarkApp.

I can configure the inbound domain in the server settings page. Inbound domains are unique across Postmark and are server-specific.

So i went on my PostmarkApp's server's setting page i went ahead and inside the Inbound Domain i gave a random name, to ensure there are no conflicts with other inbound domains from other users/servers inside PostmarkApp.

I got an error with this accompanying message: "We could not find an MX record pointing to inbound.postmarkapp.com for this domain."

I don't even understand the nature of this message. I thought i would set up my inbound domain for my server on Postmark. Then i would go to my dns records on my domain and give an MX record of 10:myserversname.postmarkapp.com

So what do i put inside the Inbound Domain settings in order to create the effect i want?

  • But if i do so.. then how does my mail go to my server in Postmark and not someone else's server? How does Postmark know that this domain belongs to me? Also, what do i put inside the Inbound Domain setting in Postmark?
    – John John
    Commented May 30, 2016 at 23:40
  • I've removed my comment above & added an answer to elaborate on this a bit further.
    – Tim Malone
    Commented May 30, 2016 at 23:50

2 Answers 2


You need to add the MX record to your domain first - go to your domain's DNS records (wherever these are managed), and add an MX record for your subdomain to point its mail to inbound.postmarkapp.com with a priority of 10.

For example:

sub.john-john.com MX inbound.postmarkapp.com 10

In Postmark's documentation, inbound.postmarkapp.com isn't just an example - it's the address of their inbound mail server and is where you need to point your MX to - and is also where they ask all of their inbound customers to point their MX records to.

How will Postmark then know where to deliver your mail to? They'll deliver it based on where it is addressed. Firstly, the sending server will do a DNS lookup of your domain, find inbound.postmarkapp.com, and then contact Postmark's server to say "I've got an e-mail for [email protected], can you accept that?" Because your subdomain is indeed set up with Postmark, Postmark will then accept the message and deliver it accordingly.

As for what to call your subdomain, if you own your own domain, it's completely up to you. I've just used sub and john-john.com in this example, but replace that with whatever your domain is and whatever you would like your subdomain to be. :)


Tim is correct. You will need to point a subdomain on your domain to inbound.postmarkapp.com, using an MX record.

So, inbound.yourdomain.com will have an MX record of inbound.postmarkapp.com with a priority of 10.

Then, when verified in Postmark, you can send emails to [email protected].

  • I don't think this is entirely correct - I haven't used Postmark, but I would think inbound.postmarkapp.com refers to the mail server not necessarily the subdomain to receive mail at. eg. the subdomain can be anything you set up, it doesn't have to be inbound but the MX record does have to be inbound.postmarkapp.com
    – Tim Malone
    Commented May 30, 2016 at 20:11
  • Hi Tim, that was just an example. It would look like: inbound.yourdomain.com IN MX 10 inbound.postmarkapp.com. Where "inbound.yourdomain.com" could be any domain with an MX record. It does not have to be a subdomain, but usually is in Postmark since customers have their domain email hosted somewhere else. We run into this a lot (I'm the founder of Postmark). Commented Jun 1, 2016 at 14:05
  • Got it. The OP was confused about 'inbound' so it's probably worthwhile using a different example so it's clear they can be separate domains. Thanks for coming here to answer, though - that's cool to have the service founder answering Q's here :)
    – Tim Malone
    Commented Jun 2, 2016 at 4:39
  • I still am confused.... Thank you for your effort...but 1. Does my subdomain have to contain the word inbound before the first dot? 2. What do i set up in the Inbound domain option in the settings? 3. How does Postmark know that the mail it receives from a domain should be forwarded to my server and not someone else's?
    – John John
    Commented Jun 3, 2016 at 0:45
  • Hi John, 1. The domain you choose to accept email can be any domain or subdomain as long as it has an MX record that points to inbound.postmarkapp.com. 2. In settings, you insert the domain that you want to receive email on. 3. By inserting your domain in settings (and pointing an MX at us) we know where to send the emails. You can email support and ask for Chris and I can help you through it as well. Commented Jun 3, 2016 at 13:18

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