NACHA File Specifications — Chase Connect

TL;DR — The fixed-width record format for US ACH payments — the plumbing under direct deposit.

June 2019. Specifications for CCD (cash concentration/disbursement), PPD (prearranged payment and deposit) and WEB (internet-initiated) ACH entries.

Every direct deposit, payroll run and autopay in the United States moves as a fixed-width record in this format. It is one of the most economically consequential file formats in existence and almost nobody has seen one — the specification is a bank implementation guide rather than a published standard.

Genuinely useful if you ever have to build against ACH, and clarifying about how old the rails are.

Where this came from

• Tim Hwang’s “greatest, rarest PDF” thread

12 pages. A copy is archived locally against link rot; the header links the original source.