Programmatic payouts: ACH, RTP, FedNow and wire
How platforms send programmatic payouts over ACH, same-day ACH, RTP, FedNow and wire: limits, speed, the treasury APIs that run them, and how to choose.
Programmatic payouts are payments your platform sends to its users automatically, through an API, over the rail that fits each payment: ACH for routine volume, same-day ACH when it has to land today, RTP or FedNow when it has to land in seconds, and wire for large single payments. Two things decide the setup: which rails you need, and who holds the money before it moves.
This guide compares the US payout rails on limits and speed, then the kinds of treasury infrastructure that run them, and closes on the part that decides whether payouts scale: reconciliation.
The payout rails compared
US platforms pay users over five rails. Each one differs on speed, cap and hours.
| Rail | Speed | Per-payment limit | Hours | Best for |
|---|---|---|---|---|
| ACH (standard) | 1–2 business days | Set by your bank | Business days, in batches | Routine payouts to many users |
| Same-day ACH | Same business day | $1 million; $10 million from 17 Sep 2027 | Business-day windows | Payouts that must land today, at ACH cost |
| RTP | Seconds | $10 million | 24/7/365 | Instant payouts, on-demand work |
| FedNow | Seconds | $10 million (network); banks may set lower | 24/7/365 | Instant payouts where RTP isn’t reachable |
| Wire (Fedwire) | Same day | No practical cap | Business-day hours | Large or urgent single payments |
Sources:
- Same-day ACH: its limit rose to $1 million in March 2022, and Nacha’s approved rule change raises it to $10 million on 17 September 2027.
- RTP: The Clearing House raised the RTP network limit to $10 million on 9 February 2025.
- FedNow: the Federal Reserve raised the FedNow network limit from $1 million to $10 million in November 2025. Participating banks can still set lower limits.
The practical rule: default to ACH, escalate to same-day ACH when the deadline is today, and use RTP or FedNow when it’s now. Wires are for the rare large payment. More on the two classic rails in ACH vs wire and on instant rails in real-time payments.
The treasury infrastructure that runs programmatic payouts
Five kinds of provider run programmatic payouts for platforms. They differ on who holds the account and which rails they reach.
| Provider type | Examples | Holds the funds | Rails | Reconciliation |
|---|---|---|---|---|
| Payment-operations software | Modern Treasury | Your banks | ACH, wire, RTP through your banks | Ledgers and reconciliation tools |
| Payout and reconciliation layer | Fynex | Safeguarded at an FCA-authorised EMI, or your existing accounts | Routed per payout to the cheapest compliant rail | Every payout posted back to Xero or QuickBooks |
| Bank with an API | Column, Increase | The bank or its partner banks | ACH, wire, instant rails | Your build |
| ACH-first payments API | Dwolla | Partner banks | ACH, with instant options | Your build |
| Platform payments | Stripe Connect | Stripe balances | Stripe payouts | Stripe reports |
The more your team wants to own the ledger, the more the bank-API end suits you. The more you want payouts to simply run and land in the books, the more the layer end suits you. Head-to-heads: Modern Treasury vs Stripe, Dwolla vs Modern Treasury, Fynex vs Modern Treasury.
What “programmatic” actually requires
A payout API is only programmatic if it handles the failure cases without a person. Check five things before you choose:
- Idempotency. A retried request must never pay a user twice.
- Rail choice per payment. Pick the rail by rule (amount, deadline, the recipient’s bank), not by code path.
- Webhooks for every state. Created, sent, settled, returned, failed, each as an event your system can act on.
- Returns as first-class objects. An ACH payment can come back after it settles, so the return has to find its original payout and reverse the right balance.
- A record that survives the rail. The user, order or invoice ID travels with the payout, so the bank statement can be matched back without guesswork.
Where payouts meet the books
Payouts scale when every payout reconciles itself. A run of 5,000 payouts leaves your bank as one debit, or as 5,000 lines with references that banks truncate. Matching them back to 5,000 users becomes a job of its own. The fix is upstream: each payout carries what it settles, and the run posts to your ledger as it happens, with failures and returns raised as exceptions against the original payout.
Where Fynex fits
Fynex runs programmatic payouts for platforms as a layer over the rails and accounts you keep. Each payout is routed by rule to the cheapest compliant rail: ACH, same-day ACH, instant or wire in the US, and local rails abroad. Funds held before payout are safeguarded at an FCA-authorised EMI. Every payout, fee and return is posted back to the order or invoice it settles, in Xero or QuickBooks. Pricing is public: 0.5% per payout, $1 minimum, plus $100 a month (pricing). See payouts.
Related: how to pay out marketplace sellers · why is my payment delayed? · ACH · wire transfer