openapi: 3.0.1
info:
  title: Mono Account Information API
  description: Specification of the Mono open-banking API. Mono lets businesses link customer bank accounts (Connect) to read transactions, statements, identity, income, and balance, and to collect payments via DirectPay one-time transfers and Direct Debit mandates. All requests are authenticated with the secret application key supplied in the mono-sec-key header. Monetary amounts are expressed in the lowest denomination of the currency (e.g. kobo for NGN).
  termsOfService: https://mono.co/legal
  contact:
    name: Mono Support
    url: https://docs.mono.co
    email: hi@mono.co
  version: '2.0'
servers:
- url: https://api.withmono.com
  description: Mono production API
security:
- monoSecKey: []
tags:
- name: Account Information
  description: Account details and balance for a linked account.
paths:
  /v2/accounts/{id}:
    get:
      operationId: getAccountDetails
      tags:
      - Account Information
      summary: Get account details
      description: Retrieves account holder, institution, and balance details for a linked account.
      parameters:
      - $ref: '#/components/parameters/AccountId'
      responses:
        '200':
          description: Account details.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/AccountDetails'
        '401':
          $ref: '#/components/responses/Unauthorized'
        '404':
          $ref: '#/components/responses/NotFound'
  /v2/accounts/{id}/balance:
    get:
      operationId: getAccountBalance
      tags:
      - Account Information
      summary: Get account balance
      description: Returns the near-real-time balance for a linked account.
      parameters:
      - $ref: '#/components/parameters/AccountId'
      responses:
        '200':
          description: Account balance.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Balance'
        '401':
          $ref: '#/components/responses/Unauthorized'
  /v2/accounts/{id}/unlink:
    post:
      operationId: unlinkAccount
      tags:
      - Account Information
      summary: Unlink account
      description: Unlinks a previously linked account, revoking further data access.
      parameters:
      - $ref: '#/components/parameters/AccountId'
      responses:
        '200':
          description: Account unlinked.
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/StatusMessage'
        '401':
          $ref: '#/components/responses/Unauthorized'
components:
  schemas:
    Error:
      type: object
      properties:
        status:
          type: string
        message:
          type: string
    StatusMessage:
      type: object
      properties:
        status:
          type: string
        message:
          type: string
    AccountDetails:
      type: object
      properties:
        meta:
          type: object
          properties:
            data_status:
              type: string
            auth_method:
              type: string
        account:
          type: object
          properties:
            id:
              type: string
            name:
              type: string
            currency:
              type: string
            type:
              type: string
            account_number:
              type: string
            balance:
              type: integer
            bvn:
              type: string
            institution:
              type: object
              properties:
                name:
                  type: string
                bank_code:
                  type: string
                type:
                  type: string
    Balance:
      type: object
      properties:
        status:
          type: string
        message:
          type: string
        data:
          type: object
          properties:
            id:
              type: string
            name:
              type: string
            account_number:
              type: string
            balance:
              type: integer
            currency:
              type: string
  parameters:
    AccountId:
      name: id
      in: path
      required: true
      description: The linked account id returned by the exchange-token endpoint.
      schema:
        type: string
  responses:
    Unauthorized:
      description: Missing or invalid mono-sec-key.
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/Error'
    NotFound:
      description: Resource not found.
      content:
        application/json:
          schema:
            $ref: '#/components/schemas/Error'
  securitySchemes:
    monoSecKey:
      type: apiKey
      in: header
      name: mono-sec-key
      description: Secret application key issued in the Mono dashboard.