ACH vs SWIFT: what is the difference?

ACH moves the money; SWIFT carries the message, and the banks settle the wire between themselves. ACH first. Nacha, which writes its rules, describes it as "a payment system that reaches all U.S. bank and credit union accounts", and the Federal Reserve, one of its operators, calls its service batched: payments are collected and cleared in windows, not one by one. They can be processed within hours on the same business day or scheduled a day or two out. ACH needs a routing number and an account number, it is domestic, and it is the cheapest way to pay anyone with a US account.

SWIFT describes itself as "a global member-owned cooperative" and a provider of secure financial messaging. It neither holds money nor moves it; it carries the instruction. The money moves through accounts the banks keep with each other, sometimes through an intermediary bank that takes its own fee, which is why an international wire takes days rather than hours, why the amount that arrives can be smaller than the amount sent, and why the recipient's bank needs a BIC (the SWIFT code) beside an IBAN or an account number. A wire can carry any currency, and whichever bank converts it prices the conversion.

Neither is the whole map. Inside the US a same-day, one-at-a-time transfer is a domestic wire, which is not ACH. In the euro area the ACH-like network is SEPA, addressed by IBAN; in the UK it is Faster Payments, addressed by sort code and account number. A "SWIFT payment" from a US bank to a German one is a wire instructed over SWIFT and credited to an IBAN.

Which to use is decided by the payee's bank, not by you. A US account in dollars: ACH. The euro area: SEPA. The UK: sort code. Everywhere else, or any currency the local network does not carry: a wire over SWIFT. For a contractor abroad the honest comparison is the fee at both ends plus the rate, which the payment cost calculator adds up, and it is the point where a stablecoin enters the conversation.

How this shows up in Orla

A contact's bank rail is entered as a form with a scheme, SEPA and IBAN, UK sort code, US ACH, or SWIFT for everywhere else, and the fields for that scheme appear. An IBAN or a US routing number with two digits swapped is refused as it is typed, the mistake that otherwise surfaces once the money is somewhere else.

From a connected Mercury account US payees are paid by ACH and everyone else by international wire, in US dollars only; Orla requests each payment into Mercury's own approval queue and never sends it. From a connected Slash account, Send via Slash creates the transfer as ACH, domestic wire or international wire, whichever way the recipient is set up there.

Sources, read on 26 September 2026

• Nacha, ACH Network: “a payment system that reaches all U.S. bank and credit union accounts”
• Federal Reserve Financial Services, FedACH Services: “batched payment services that enable an electronic exchange of debit and credit transactions through the ACH network”
• Swift, Who we are: “Swift is a global member-owned cooperative and the world's leading provider of secure financial messaging services.”