Introduction to the RMO Merchant API | RMO Developer Center, Merchant Services

Introduction to the RMO Merchant API

The RMO Merchant API allows merchants, platforms, and payment partners to securely process transactions across card-present and card-not-present channels using RMO’s unified payments network.

This API provides a modern, predictable interface for authorizing, capturing, refunding, voiding, and settling transactions. Merchants can also take advantage of PaymentCodes, a secure PIN-based alternative to stored cards, and RecurringAuthorizations, which allow merchant-initiated transactions in a compliant and member-controlled manner.

What You Can Do

  • Process authorizations (auth-only)

  • Capture funds against an existing authorization

  • Run combined sales (auth + capture)

  • Void authorizations before settlement

  • Process partial or full refunds

  • Accept PaymentCodes for CNP payments

  • Enable, charge, and revoke recurring billing

  • Retrieve transaction history

  • Access settlement batches and statements

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API Base URL

https://api.rmous.org/merchant/v1/

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Core Domains

  • MerchantServicing – Merchant accounts, PaymentCodes, RecurringAuthorizations, merchant transactions

  • FinancialServicing – Ledger transactions, account balances, statements

  • CardServicing – Card issuance, limits, statuses, card networks


Whether you’re building an e-commerce checkout, a POS integration, or a subscription platform, the RMO Merchant API provides all the core payment capabilities you need.

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