[bct]

You can do a lot worse than ACH. It's hard to read, but it's simple and pretty well-defined.

What _really_ sucks is one-off fixed-width formats that aren't well defined, or that change suddenly (oh, you thought that field would always be populated? lol no.)

[HillRat]

Yeah, ACH is surprisingly not-unpleasant, at least relative to nightmares like X12 EDI with its implicit looping constructs and billions of companion guides that supercede random parts of the base spec.

[sixdimensional]

X12 EDI, been there earned the badge, both on the generating and receiving sides. 837, 834, 835 and others in health care - fun! Positional format, with situational meaning... really it is a fascinating format.

[20after4]

Don't you mean nightmare format?

[eric_h]

Nightmares can be fascinating

[pg_is_a_butt]

i wrote the X12 EDI stuff for a major clearwater distributor... also wrote the ACH stuff that dumped someone a file and their job was to upload it via SFTP to the bank. so many badges.

[oddsignals]

What _really really_ sucks is well-defined, reasonable, meticulously documented formats where all in-the-wild implementations stray from the spec in different ways :-/

[tonyedgecombe]

Years ago I worked with a product that parsed line printer data, it was a nightmare trying to get every piece of optional data into the reports.