| Measuring deliverability is really not that hard. You do the following: - Setup blacklist monitoring (e.g. HetrixTools/MXToolbox) - Check if you can email Gmail - Check if you can email Hotmail - Check if you can email Office365 - Check on Microsoft SNDS that you are not blocked: https://sendersupport.olc.protection.outlook.com/snds/ Gmail, Hotmail and Office365 are the largest email providers and also the most strict ones. I have accounts on all of these providers so testing deliverability is trivial. You could argue that testing deliverability with one account is unreliable but in my experience it simply is not. Usually you send a couple emails across a week and if they all go through you are good. If you are paranoid, you can ask if any of your friends have Office365/Hotmail and email them. They probably have company or university accounts on there. My server has only been blocked once after all this, and ironically it was by another company that self-hosts their email... |
No, it's not trivial, and no, it doesn't work like that. It's fairly easy to get a test email to your own gmail/hotmail/office365 account delivered. It doesn't mean your other emails get delivered.
For example, when I needed to send out a link for my wedding photographs to my wedding guests, I did exactly what you suggested: I sent a few test emails to Gmail and Hotmail test accounts that I had set up, confirmed that they delivered, and then proceeded to send the actual email which had a link and like 50 people in the BCC field. Guess what happened: all the Gmail accounts placed my email in the spam folder. So then I had to later send another email, using a different email provider, asking people to check their spam boxes for the link (this time not including the link in the body of the email with the hope that it would increase the chances of delivery).
Note that this particular anecdote is not of self hosting email, it was using Migadu (I was initially not trusting that they can deliver email properly, so I ran those tests like you suggested, concluded that they seem to be delivering email, and then my actual real email was not delivered).