OPay
OPay Cashier API

The OPay Cashier API is the primary merchant payment API behind OPay Checkout. It exposes a hosted Express Checkout endpoint (cashier/create returning a cashierUrl), server-to-server payment creation for 3DS bank cards, bank transfer, bank USSD, bank account, POS, OPay wallet QR, and reference code payments, plus status queries, cancel, refund, and refund-status operations. Authentication uses an Authorization Bearer token — the public key for cashier/create and an HMAC-SHA512 signature over the JSON body (signed with the merchant's private key) for all other endpoints — along with a MerchantId header.
OPay Cashier API is published by OPay on the APIs.io network, described by a machine-readable OpenAPI specification.
Tagged areas include Payments, Cashier, Checkout, Cards, and Bank Transfer. The published artifact set on APIs.io includes API documentation, a getting-started guide, authentication docs, an API reference, and an OpenAPI specification.
Documentation GitHub OpenAPI
OpenAPI Specification

openapi: 3.0.3
info:
  title: OPay Cashier API
  version: '1.0'
  description: |
    The OPay Cashier API is the merchant payment API behind OPay Checkout. It
    exposes a hosted Express Checkout endpoint plus server-to-server endpoints
    for 3DS bank card, bank transfer, bank USSD, bank account, POS, OPay
    wallet QR, and reference-code payments, with status query, cancel,
    refund, and refund-status operations.

    Authentication uses an `Authorization: Bearer <token>` header plus a
    `MerchantId` header. For `cashier/create` the bearer token is the
    merchant's public key. For all other endpoints the bearer token is an
    HMAC-SHA512 signature computed over the JSON request body using the
    merchant's private key.
  contact:
    name: OPay Merchant Support
    url: https://support.opaycheckout.com/support/ticket
  license:
    name: OPay Merchant Terms
    url: https://www.opayweb.com/terms-and-conditions
servers:
  - url: https://liveapi.opaycheckout.com/api/v1/international
    description: Production
  - url: https://testapi.opaycheckout.com/api/v1/international
    description: Sandbox
tags:
  - name: Cashier
    description: Hosted Express Checkout and order status.
  - name: Payments
    description: Server-to-server payment creation across payment methods.
  - name: Refunds
    description: Refund creation and status.
paths:
  /cashier/create:
    post:
      tags:
        - Cashier
      summary: Create Hosted Cashier Payment Order
      description: |
        Create a hosted Express Checkout order. Returns a `cashierUrl` that
        the merchant redirects the customer to in order to complete payment
        on an OPay-branded checkout page. Authenticate with the merchant's
        public key as the bearer token.
      operationId: createCashierPayment
      security:
        - PublicKeyAuth: []
      parameters:
        - $ref: '#/components/parameters/MerchantIdHeader'
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/CashierCreateRequest'
      responses:
        '200':
          description: Cashier order created.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/CashierCreateResponse'
  /cashier/status:
    post:
      tags:
        - Cashier
      summary: Query Payment Status
      description: |
        Query the status of a payment order by merchant reference or by OPay
        orderNo. Authenticate with an HMAC-SHA512 signature of the JSON body
        as the bearer token.
      operationId: queryPaymentStatus
      security:
        - SignatureAuth: []
      parameters:
        - $ref: '#/components/parameters/MerchantIdHeader'
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/PaymentStatusRequest'
      responses:
        '200':
          description: Order status returned.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/PaymentStatusResponse'
  /payment/create:
    post:
      tags:
        - Payments
      summary: Create Server Payment
      description: |
        Server-to-server payment creation. The `payMethod` field selects the
        payment method — `BankCard` (3DS), `BankTransfer`, `BankUSSD`,
        `BankAccount`, `POS`, `OPay`, or `ReferenceCode`. The response
        contains a `nextAction` describing what the merchant must do next
        (redirect for 3DS, display a virtual transfer account, display a
        USSD code, etc.). Authenticate with an HMAC-SHA512 signature of the
        JSON body as the bearer token.
      operationId: createPayment
      security:
        - SignatureAuth: []
      parameters:
        - $ref: '#/components/parameters/MerchantIdHeader'
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/PaymentCreateRequest'
      responses:
        '200':
          description: Payment created.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/PaymentCreateResponse'
  /payment/refund:
    post:
      tags:
        - Refunds
      summary: Refund Payment
      description: |
        Refund a previously settled payment, in full or in part. Authenticate
        with an HMAC-SHA512 signature of the JSON body as the bearer token.
      operationId: refundPayment
      security:
        - SignatureAuth: []
      parameters:
        - $ref: '#/components/parameters/MerchantIdHeader'
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/RefundRequest'
      responses:
        '200':
          description: Refund accepted.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/RefundResponse'
  /payment/refund/status:
    post:
      tags:
        - Refunds
      summary: Query Refund Status
      description: |
        Query the status of a refund by merchant refundReference or by OPay
        refundOrderNo. Authenticate with an HMAC-SHA512 signature of the
        JSON body as the bearer token.
      operationId: queryRefundStatus
      security:
        - SignatureAuth: []
      parameters:
        - $ref: '#/components/parameters/MerchantIdHeader'
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/RefundStatusRequest'
      responses:
        '200':
          description: Refund status returned.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/RefundStatusResponse'
components:
  securitySchemes:
    PublicKeyAuth:
      type: http
      scheme: bearer
      description: Bearer token = merchant public key (used for cashier/create).
    SignatureAuth:
      type: http
      scheme: bearer
      description: Bearer token = HMAC-SHA512 of the JSON request body signed with the merchant private key.
  parameters:
    MerchantIdHeader:
      name: MerchantId
      in: header
      required: true
      schema:
        type: string
      description: The merchant identifier issued by OPay (e.g. 256612345678901).
  schemas:
    Amount:
      type: object
      required: [total, currency]
      properties:
        total:
          type: integer
          format: int64
          description: Amount in the smallest currency unit (e.g. kobo / cent).
        currency:
          type: string
          description: ISO-4217 currency code.
          example: NGN
    Product:
      type: object
      properties:
        name:
          type: string
        description:
          type: string
    UserInfo:
      type: object
      properties:
        userId:
          type: string
        userName:
          type: string
        userEmail:
          type: string
        userMobile:
          type: string
    BankCard:
      type: object
      properties:
        cardHolderName:
          type: string
        cardNumber:
          type: string
        cvv:
          type: string
        expiryMonth:
          type: string
        expiryYear:
          type: string
        enable3DS:
          type: boolean
    NextAction:
      type: object
      description: Instructions for the next step required to complete the payment.
      properties:
        actionType:
          type: string
          enum:
            - REDIRECT_3DS
            - TRANSFER_ACCOUNT
            - USSD
            - QR_CODE
            - REFERENCE_CODE
        redirectUrl:
          type: string
        transferAccountNumber:
          type: string
        transferBankName:
          type: string
        expiredTimestamp:
          type: integer
          format: int64
    PaymentStatus:
      type: string
      enum:
        - INITIAL
        - PENDING
        - SUCCESS
        - FAIL
        - CLOSE
    PayMethod:
      type: string
      enum:
        - BankCard
        - BankTransfer
        - BankUSSD
        - BankAccount
        - POS
        - OPay
        - ReferenceCode
    ApiEnvelope:
      type: object
      properties:
        code:
          type: string
          example: '00000'
        message:
          type: string
          example: SUCCESSFUL
    CashierCreateRequest:
      type: object
      required: [reference, country, amount, returnUrl, product]
      properties:
        reference:
          type: string
          description: Unique merchant order reference.
        country:
          type: string
          example: NG
        amount:
          $ref: '#/components/schemas/Amount'
        returnUrl:
          type: string
        callbackUrl:
          type: string
        cancelUrl:
          type: string
        payMethod:
          $ref: '#/components/schemas/PayMethod'
        product:
          $ref: '#/components/schemas/Product'
        userInfo:
          $ref: '#/components/schemas/UserInfo'
        expireAt:
          type: integer
          description: Order expiry, in minutes (default 30).
        displayName:
          type: string
        sn:
          type: string
        evokeOpay:
          type: string
        customerVisitSource:
          type: string
    CashierCreateResponse:
      allOf:
        - $ref: '#/components/schemas/ApiEnvelope'
        - type: object
          properties:
            data:
              type: object
              properties:
                cashierUrl:
                  type: string
                orderNo:
                  type: string
                reference:
                  type: string
                status:
                  $ref: '#/components/schemas/PaymentStatus'
                amount:
                  $ref: '#/components/schemas/Amount'
                vat:
                  $ref: '#/components/schemas/Amount'
    PaymentStatusRequest:
      type: object
      properties:
        reference:
          type: string
        orderNo:
          type: string
        country:
          type: string
          example: NG
    PaymentStatusResponse:
      allOf:
        - $ref: '#/components/schemas/ApiEnvelope'
        - type: object
          properties:
            data:
              type: object
              properties:
                reference:
                  type: string
                orderNo:
                  type: string
                status:
                  $ref: '#/components/schemas/PaymentStatus'
                amount:
                  $ref: '#/components/schemas/Amount'
                createTime:
                  type: integer
                  format: int64
    PaymentCreateRequest:
      type: object
      required: [reference, country, amount, payMethod, product]
      properties:
        reference:
          type: string
        country:
          type: string
          example: NG
        amount:
          $ref: '#/components/schemas/Amount'
        payMethod:
          $ref: '#/components/schemas/PayMethod'
        product:
          $ref: '#/components/schemas/Product'
        callbackUrl:
          type: string
        returnUrl:
          type: string
        customerName:
          type: string
        userInfo:
          $ref: '#/components/schemas/UserInfo'
        userPhone:
          type: string
        bankcard:
          $ref: '#/components/schemas/BankCard'
    PaymentCreateResponse:
      allOf:
        - $ref: '#/components/schemas/ApiEnvelope'
        - type: object
          properties:
            data:
              type: object
              properties:
                reference:
                  type: string
                orderNo:
                  type: string
                status:
                  $ref: '#/components/schemas/PaymentStatus'
                amount:
                  $ref: '#/components/schemas/Amount'
                nextAction:
                  $ref: '#/components/schemas/NextAction'
    RefundRequest:
      type: object
      required: [refundReference, country, amount]
      properties:
        refundReference:
          type: string
          description: Unique merchant refund reference.
        orderNo:
          type: string
          description: OPay orderNo of the original payment.
        reference:
          type: string
          description: Merchant reference of the original payment.
        country:
          type: string
          example: NG
        amount:
          $ref: '#/components/schemas/Amount'
        reason:
          type: string
    RefundResponse:
      allOf:
        - $ref: '#/components/schemas/ApiEnvelope'
        - type: object
          properties:
            data:
              type: object
              properties:
                refundOrderNo:
                  type: string
                refundReference:
                  type: string
                status:
                  type: string
                  enum: [PENDING, SUCCESS, FAIL]
                amount:
                  $ref: '#/components/schemas/Amount'
    RefundStatusRequest:
      type: object
      properties:
        refundReference:
          type: string
        refundOrderNo:
          type: string
        country:
          type: string
          example: NG
    RefundStatusResponse:
      allOf:
        - $ref: '#/components/schemas/ApiEnvelope'
        - type: object
          properties:
            data:
              type: object
              properties:
                refundReference:
                  type: string
                refundOrderNo:
                  type: string
                status:
                  type: string
                  enum: [PENDING, SUCCESS, FAIL]
                amount:
                  $ref: '#/components/schemas/Amount'
OPay Cashier API

Documentation

Specifications

Other Resources

OpenAPI Specification
