Zine - Reading RFCs - Email

Welcome back! ♥️ In 2018, I wrote a Twitter thread that went semi-viral after I did some research about email RFCs and found some fun examples of email addresses that are valid but not well supported.

Since the Twitter thread has since been deleted (sadface), it motivated me to turn it into the tiny zine you are holding, or viewing online.

I’ve done my best to fix any inaccuracies, provide more consistent examples and update everything based on errata.


Lots of RFCs are informational or experimental in nature and are not standards, therefore just because an RFC states an address is valid, it doesn’t mean that a mail server MUST accept it.

For example RFC 3696 “Application Techniques for Checking and Transformation of Names” which you will see cited here quite a bit is categorised as Informational which as outlined in RFC 2026 is “for the general information of the Internet community, and does not represent an Internet community consensus or recommendation”.

Enjoy 🚀

Zine - Reading RFCs - Email by errbufferoverfl