Recently a client who uses Mailgun to send email from their website had a problem where one of the clients own email addresses had been “suppressed” in Mailgun, meaning Mailgun would no longer send email to that address. It was caused by the client’s mail server having a problem for long enough that Mailgun decided they couldn’t send email to the particular address.

Mailgun have the ability to “whitelist” individual email addresses or whole domains so they will not stop sending to them. That’s exactly what I needed to put in a long term fix for this problem. It’s not available through their website, but you can do it through their API. That was fine, we’re using the API for other things so I can adapt some code to use it for this.

Unfortunately, the docs for whitelisting an email address are currently incorrect. I had some back and forth with their support people and they gave me the following curl example for how to whitelist an email address:

curl -i -X POST  -u api:[your api key] https://api.eu.mailgun.net/v3/[your mailgun domain]/whitelists -F address=[your email address]

Where [your api key] and [your mailgun domain] and [your email address] get replaced by your details.

Remember that if you’re in Europe, you’re probably using the EU API, not the one in the docs, so you’ll need to change the API domain to https://api.eu.mailgun.net

To whitelist a whole domain, use:

curl -i -X POST  -u api:[your api key] https://api.mailgun.net/v3/[your mailgun domain]/whitelists -F domain=[your email domain]

Finally, to check the whitelist, use this:

curl -i -X GET  -u api:[your api key]  https://api.mailgun.net/v3/[your mailgun domain]/whitelists

This was a frustrating situation as it took a while for their support to understand that giving me back the incorrect examples from the docs wasn’t helping, but they did come through for us in the end and were polite and trying to be helpful throughout. Hopefully they’ll get their docs updated soon.