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The Open Money Stack (OMS) Payments API moves money between fiat and stablecoins. It provides the full infrastructure stack: identity, custodial wallets, compliance, and fiat rail access, all integrated so they hand off cleanly to each other. One integration covers fiatToCrypto, cryptoToFiat, and cryptoToCrypto transactions across ACH, wire, SWIFT, cash, and card rails.

Get started

Onboard a customer, provision a wallet, and make your first transaction.

API reference

Full endpoint reference: transactions, quotes, wallets, customers, webhooks.

Core concepts

Entities & relationships

The core resources (customers, wallets, quotes, transactions, and cash-ins), the early-access concepts (virtual accounts, deposit addresses, and external accounts), and how they relate.

Quote system

How OMS locks pricing, structures fees, and calculates exchange rates before you commit to a transaction.

Account model

Custodial wallets, virtual bank accounts, deposit addresses, and external accounts.

Transaction lifecycle

Statuses, sub-statuses, webhook events, and auto-created transactions from deposit flows.

Currencies & rails

Supported assets, networks, and fiat rails: ACH, SEPA, PIX, UPI, SPEI, cash networks, and stablecoins.

Use cases

Common products built on the Open Money Stack. Each card links to a step-by-step walkthrough.

Dollar accounts

Give users a real USD account number that receives ACH transfers and holds a stablecoin balance.

On-ramp via cash

Fund a digital wallet with physical cash at retail locations.

Consumer on-ramp and off-ramp

Fund a wallet with cash-in, hold a USDC balance, and withdraw to a bank account.

Payroll and disbursements

Pay contractors and employees in local currency from a single treasury wallet.

Cross-border remittance

Fiat in one country, fiat delivered in another, settled via Polygon in seconds.

Cash disbursements

Convert a wallet balance to physical cash via retail or ATM pickup codes.

OMS primitives

The OMS API is managed through a core set of resources. Every transaction, deposit, and disbursement is built from these.

Customers

An identity record with KYC endorsements that gates access to financial operations. Every wallet belongs to a customer.

Wallets

Custodial or non-custodial stablecoin balances on Polygon. Source or destination for any transaction.

Quotes

A rate lock with full fee breakdown. Created before every transaction. Expires if not executed within the validity window.

Transactions

Execute a quoted money movement: fiatToCrypto, cryptoToFiat, or cryptoToCrypto. Track status via webhooks through processing to completed.

Cash-ins

A code-based deposit flow for in-person cash funding at retail locations. Auto-creates a fiatToCrypto transaction on confirmation.

Webhooks

Subscribe to status changes across customers, transactions, and cash-ins. Full create, read, update, and delete support.

Early-access concepts

The following are part of the OMS model but are not yet available in the OMS API. They are referenced as inputs in quote and transaction bodies today.

Virtual accounts

A dedicated US bank account number assigned to a customer. Incoming ACH deposits auto-convert to USDC.

Deposit addresses

A persistent onchain address for a customer’s wallet. Incoming crypto auto-triggers a transaction.

External accounts

A customer’s bank account, referenced by ID as a destination for off-ramps. Early access.

Why Polygon for settlement

  • Sub-2-second finality with 99.9%+ network uptime
  • $0.002 average transaction cost on Polygon Chain
  • $54B+ in stablecoin transfer volume processed onchain
  • Native USDC: no wrapping, no bridging, no surprise deductions
  • Compliance included: KYC, KYB, AML screening, and transaction monitoring across 38 US states and international corridors