NMI · Authentication Profile

Nmi Authentication

Authentication

NMI secures its APIs with apiKey and oauth2 across 2 declared security schemes, as derived from its OpenAPI definitions. OAuth 2.0 is offered via the clientCredentials flow(s).

PaymentsPayment GatewayPayment ProcessingTokenizationRecurring BillingCustomer VaultFintechEmbedded PaymentsPayment Facilitation

Methods: apiKey, oauth2 Schemes: 2 OAuth flows: clientCredentials API key in: header

Security Schemes

v4ApiKey apiKey

· in: header (Authorization)

oauth oauth2

· flows: clientCredentials

Source

Authentication Profile

generated: '2026-10-14'
method: derived
source: openapi/nmi-authvia-openapi.yml, openapi/nmi-payments-api-openapi.yml, openapi/nmi-payments-sign-up-api-openapi.yml
summary:
  types:
  - apiKey
  - oauth2
  api_key_in:
  - header
  oauth2_flows:
  - clientCredentials
schemes:
- name: v4ApiKey
  type: apiKey
  in: header
  parameter: Authorization
  description: API Security Key assigned to a partner or merchant account. New keys can be generated
    from Settings > Security Keys in the partner and merchant portals.
  sources:
  - openapi/nmi-authvia-openapi.yml
  - openapi/nmi-payments-api-openapi.yml
- name: oauth
  type: oauth2
  flows:
  - flow: clientCredentials
    tokenUrl: /oauth/token
    scopes: 6
  sources:
  - openapi/nmi-payments-sign-up-api-openapi.yml

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