SET API (Platforms)

For B2B platforms (vertical software, marketplaces, payment service providers) that onboard their own merchants and want each merchant paid through accounts in the merchant's own name. The platform calls SET; each merchant is verified and becomes a customer in its own right.

The flow

Name the merchant: POST /v1/customers. In production the answer carries the hosted terms and verification links.
The merchant is verified (KYB): GET /v1/customers/{id} reaches approved, with the currencies it may use.
Say how the merchant is paid, in one call: POST /v1/payment_setups with way wallet, cash_out or bank and the merchant's details for that way.
Hand over payTo: exactly what the merchant gives its payers.
Follow the money: webhooks or GET /v1/events; GET /v1/reports/monthly for reconciliation.

The separate calls (bank accounts, Cash-Out Addresses, virtual accounts) stay available for platforms that want each step.

Currencies and rails

Currency	Collect (virtual account)	Pay out (Cash-Out Address)	Endorsement
USD	ACH, wire, FedNow (account in the merchant's name)	ACH (default) or wire to the merchant's US account	`base`
EUR	Virtual IBAN, SEPA standard and instant	SEPA to the merchant's IBAN	`sepa`
GBP	UK sort code and account number, Faster Payments	Faster Payments to the merchant's UK account	`faster_payments`

Stablecoins delivered or accepted: USDC on Base, Ethereum, Polygon, Arbitrum, Optimism, Avalanche and Solana; USDT on Ethereum and Solana; PYUSD; EURC on Base, Ethereum and Solana, each where the provider lists the route. RTP is not offered (FedNow is); USDT on Tron is not offered; no rate is ever locked.

Platforms stay out of the flow of funds

By default a platform never receives or holds its merchants' money:

A destination wallet must be the merchant's own (beneficiary: {type: "customer", …}); {type: "platform"} is refused with 403 platform_funds_not_allowed.
Every Cash-Out or Conversion Address needs a returnAddress the merchant controls; the platform cannot register a default return address.

SET switches platform funds on for one platform only after its own review of that platform's licences and programme (Platform oversight).

Compliance responsibilities

	SET	The platform
Verifies the platform (KYB)	Yes	—
Verifies each merchant	Through hosted KYB/KYC; SET's own risk rating and screening on top	Its own programme, separately
Screens against sanctions lists	Every customer, owner and counterparty SET learns of	Its own customers
Names payers (Travel Rule)	Refuses movements without required data	Sends `/sender` for each payment it can identify
Monitors transactions, escalates and reports	Yes, under SET's programme	Yes, under its own
Answers requests for information	Collects from the platform within 5 business days	Must answer SET

SET's programme stands on its own: it does not rely on the platform's programme to meet SET's obligations, and the platform's programme does not rely on SET's. See Compliance.

Calls

See the call list in the sidebar, grouped as Account, Customers, Payment setups, Bank accounts, Cash-Out Addresses, Virtual accounts, Deposits, Cash-Out payments, Conversion, Wallets, Return addresses, Events & webhooks, Tools and Sandbox. Wallets are custodial USDC wallets held by Bridge for a verified merchant, withdrawable only to that merchant's own bank; a merchant with only a bank account can use one as its own return address. SET Invoices are for merchant keys only (SET Merchant API).