so now in theory I could write a script that pulls down the email, decrypts, verifys the amount, sends a bitcoin payment, updates my records. all the the click of a button. so much more civilized than pdf invoices.

I just suffered emotional damage reading that 🤣

There are a number of EDI formats besides ANSI. EDIFACT (EU version), CATAIR (USCS 80 column punched card version), etc. The only format I loath is XML.

one liner to get the subtotal from my inbox:

notmuch show --format=raw subject:invoice and from:daniel and tag:inbox | grep -A1000 "Content-Type: application/octet-stream" - | grep -v -e "^--" -e "Content-" | base64 -d | gpg -d | yq .subtotal