# NMI Payment API

**Canonical:** https://apis.io/apis/nmi/nmi-payment-api/  
**Provider:** NMI — https://apis.io/providers/nmi/  
**Base URL:** https://secure.networkmerchants.com  
**Documentation:** https://docs.nmi.com/reference/getting-started

NMI Payment API is one of 8 APIs that [NMI](https://apis.io/providers/nmi/) publishes on the [APIs.io](https://apis.io/) network, described by a machine-readable OpenAPI specification. Tagged areas include Payments, Transaction, Authorization, and Refunds. The published artifact set on APIs.io includes API documentation and an OpenAPI specification.

The core NMI Payment API (Direct Post) enables transaction processing across card-present, ecommerce, mobile, and alternative payment methods including Apple Pay and Google Pay. Supports authorization, sale, capture, refund, void, credit, and validation operations with credential-on-file and partial payment support.

## Machine-readable artifacts (4)

- **Documentation** — https://docs.nmi.com/docs
- **OpenAPI** — https://docs.nmi.com/reference/getting-started
- **Sandbox** — https://docs.nmi.com/docs/sandbox-testing
- **APIsJSON** — https://raw.githubusercontent.com/api-evangelist/nmi/refs/heads/main/apis.yml

## Other NMI APIs (7)

- [NMI Customer Vault API](https://apis.io/apis/nmi/nmi-customer-vault-api/)
- [NMI Recurring Billing API](https://apis.io/apis/nmi/nmi-recurring-billing-api/)
- [NMI Query API](https://apis.io/apis/nmi/nmi-query-api/)
- [NMI Merchant Onboarding API](https://apis.io/apis/nmi/nmi-merchant-onboarding-api/)
- [NMI Webhooks API](https://apis.io/apis/nmi/nmi-webhooks-api/)
- [NMI Three Step Redirect API](https://apis.io/apis/nmi/nmi-three-step-redirect-api/)
- [NMI Customer-Present Cloud API](https://apis.io/apis/nmi/nmi-customer-present-cloud-api/)

## Tags

Payments, Transaction, Authorization, Refunds

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Profiled by [API Evangelist](https://apievangelist.com) and published on [APIs.io](https://apis.io/apis/nmi/nmi-payment-api/). The API's provider profile, Kin Score and agent-readiness rating are at https://apis.io/providers/nmi/.