Reference
Payment-ops reference, in plain words.
What an ACH return or NOC code means and what to do about it, which SEC code a payment needs, when the Fed, TARGET2 and UK payment systems close, and how each country’s IBAN is built. Every page uses the same data as the tools, the REST API and the MCP server.
71 code pages
ACH return codes
R01 to R85 and the coming R90: what each means, the return timeframe, consumer or corporate, and what to do next.
23 code pages
NOC codes
The Notification of Change codes in use with their corrected-data layouts, the retired ones, and the refused NOC codes.
23 codes
SEC codes
PPD, CCD, CTX, WEB, TEL and the rest: what each is for and which one a payment needs.
3 calendars by year
Bank holidays
Federal Reserve (ACH and Fedwire), TARGET2 and UK closing days by year, with what they do to settlement.
89 countries
IBAN formats
Length, BBAN structure, bank code positions and an example for every IBAN country.
Pairs with the tools
The reference explains; the tools compute. Turn a return code and a settlement date into a deadline with the ACH date calculator, add business days on any calendar with the business day calculator, check an account with the IBAN validator or the routing number validator, and search every code at once in the payment code lookup.
AI agents get the same data from the REST API and the MCP server (lookup_payment_code, list_bank_holidays, validate_iban), with no key.
Sources: the Nacha Operating Rules (codes), the Federal Reserve, the ECB and gov.uk (holidays) and the SWIFT IBAN Registry (IBAN formats), summarized in this site’s words. Informational only — not a substitute for the Rules, the registry or your bank’s agreements.