ACH Processing & NACHA Reconciliation Architecture
Navigating multi-day settlement cycles, SEC code variations, and return windows with deterministic ledger verification.
The Anatomy of NACHA File Structure and Record Types
Reconciliation begins at the binary file layer. Systems must parse standard NACHA record types: Type 1 (File Header containing Immediate Origin and Destination routing numbers), Type 5 (Company/Batch Header with SEC codes like WEB, PPD, or CCD), Type 6 (Entry Detail containing individual transaction amounts, account numbers, and 15-digit trace numbers), and Type 7 (Addenda records carrying remittance data). Discrepancies often emerge when downstream bank reporting aggregates multiple batches into a single lump settlement.
Handling Multi-Day Settlement and Return Code Windows
Unlike instant payment rails, ACH transactions settle in distinct windows (Same Day ACH vs Standard ACH). Reconciling entities must track the lifecycle of each payment from Originated to Settled, Pending Return, and Reconciled. Return codes like R01 (Insufficient Funds), R02 (Account Closed), and R03 (No Account/Unable to Locate) require automated unwinding of provisional ledger credits and immediate re-balancing of customer virtual balances.
Automated ACH Invariant Verification with the NAYA Proof Engine
The NAYA Proof Engine connects ODFI file submissions directly to FedACH clearing reports and internal ledger state. It runs continuous two-way and three-way matching across trace numbers, batch totals, and net settlement entries, emitting cryptographic proof that all transit balances match verified bank holdings.
Frequently Asked Questions
Common questions about this topic
QWhat is Same-Day ACH?
A faster window that settles on the same day if submitted before specific deadlines (e.g., 10:30 AM ET). It costs slightly more and has transaction limits (currently $1M), but reduces the settlement risk window significantly.
QWhat is an NOC (Notification of Change)?
An NOC code (e.g., C01) means the payment went through, but the account details were slightly wrong (e.g., invalid account number structure that the bank auto-corrected). Your system must parse NOCs and automatically update the user's stored bank details to prevent future declines.
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