Payflex Authentication API

openapi: 3.1.0
info:
  title: Payflex Merchant Authentication API
  description: 'REST API for integrating Payflex Buy Now Pay Later (BNPL) installment payments into e-commerce platforms. Supports order creation with hosted or embedded checkout flows, order status retrieval, full and partial refunds, merchant configuration retrieval, and OAuth2 client-credentials authentication. Merchants provide customer details, billing/shipping addresses, and order amounts; Payflex returns a redirect URL and order token to complete the payment flow. Payflex pays merchants the full purchase amount upfront (less a commission) and assumes all credit and fraud risk.

    '
  version: 1.0.0
  contact:
    name: Payflex Merchant Support
    email: merchants@payflex.co.za
    url: https://payflex.co.za/support/
  termsOfService: https://payflex.co.za/terms-conditions/
  license:
    name: Proprietary
    url: https://payflex.co.za/terms-conditions/
servers:
- url: https://api.payflex.co.za
  description: Production
- url: https://api.uat.payflex.co.za
  description: Sandbox (UAT)
security:
- bearerAuth: []
tags:
- name: Authentication
  description: OAuth2 client credentials token endpoint
paths:
  /auth/merchant:
    post:
      tags:
      - Authentication
      summary: Obtain an OAuth2 access token
      description: 'Exchange client credentials (client_id and client_secret) for a Bearer access token using the OAuth2 client_credentials grant type. Tokens are short-lived and should be cached until near expiry. Production auth endpoint: https://auth.payflex.co.za/auth/merchant. Sandbox auth endpoint: https://auth-uat.payflex.co.za/auth/merchant.

        '
      operationId: getAccessToken
      security: []
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/TokenRequest'
            example:
              client_id: your-client-id
              client_secret: your-client-secret
              audience: https://auth-production.payflex.co.za
              grant_type: client_credentials
      responses:
        '200':
          description: Access token issued successfully
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/TokenResponse'
        '400':
          description: Invalid request parameters
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorResponse'
        '401':
          description: Invalid client credentials
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/ErrorResponse'
components:
  schemas:
    TokenResponse:
      type: object
      properties:
        access_token:
          type: string
          description: Bearer token for API authentication
          example: eyJhbGciOiJSUzI1NiIsInR5cCI6IkpXVCJ9...
        token_type:
          type: string
          example: Bearer
        expires_in:
          type: integer
          description: Token lifetime in seconds
          example: 3600
    ErrorResponse:
      type: object
      properties:
        errorCode:
          type: string
          description: Machine-readable error code
          example: UNAUTHORIZED
        message:
          type: string
          description: Human-readable error description
          example: Access token is missing or invalid
    TokenRequest:
      type: object
      required:
      - client_id
      - client_secret
      - audience
      - grant_type
      properties:
        client_id:
          type: string
          description: Merchant client identifier issued by Payflex
          example: your-client-id
        client_secret:
          type: string
          description: Merchant client secret issued by Payflex
          example: your-client-secret
        audience:
          type: string
          description: 'OAuth2 audience — production: https://auth-production.payflex.co.za, sandbox: https://auth-dev.payflex.co.za

            '
          example: https://auth-production.payflex.co.za
        grant_type:
          type: string
          enum:
          - client_credentials
          description: OAuth2 grant type — must be client_credentials
          example: client_credentials
  securitySchemes:
    bearerAuth:
      type: http
      scheme: bearer
      bearerFormat: JWT
      description: 'OAuth2 Bearer token obtained from the /auth/merchant endpoint using the client_credentials grant. Tokens expire and should be refreshed automatically before expiry.

        '
externalDocs:
  description: Payflex Developer Documentation
  url: https://docs.payflex.co.za/