I've gone through a number of pages and PDFs within the Paypal guides and x.com, but I can't find any reference to the maximum field lengths for the API login/connection. I see the Transaction ID maxes out at 19 characters, but they seem to avoid saying the maximums for the access fields.
I'm setting up a database table to hold multiple Paypal API logins as well as a section to edit it with I'll have validate by length. I want to use some real values instead of guessing 255 characters.
Surely someone must have been as specific as me in this regard, I'm hoping someone has found this answer.