openapi: 3.1.0
info:
  title: HMRC VAT (Making Tax Digital) Liabilities Returns API
  description: The HMRC VAT Making Tax Digital (MTD) API enables VAT-registered businesses and agents to submit VAT returns, view VAT obligations, liabilities, and payments, in compliance with UK Making Tax Digital requirements. Requires OAuth 2.0 authentication and mandatory fraud prevention headers on all requests.
  version: 1.0.0
  contact:
    name: HMRC Developer Hub
    url: https://developer.service.hmrc.gov.uk/
  license:
    name: Open Government Licence v3.0
    url: https://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/
servers:
- url: https://api.service.hmrc.gov.uk
  description: HMRC Production API
- url: https://test-api.service.hmrc.gov.uk
  description: HMRC Sandbox (test) environment
security:
- OAuth2UserRestricted: []
tags:
- name: Returns
  description: VAT return submission
paths:
  /organisations/vat/{vrn}/returns:
    post:
      operationId: submitVatReturn
      summary: Submit a VAT return
      description: Submits a VAT return for the specified VRN and period key. The return must be for an open obligation. Duplicate submissions are rejected. Finalisation is indicated by the 'finalised' field being true.
      tags:
      - Returns
      parameters:
      - name: vrn
        in: path
        required: true
        schema:
          type: string
          pattern: ^\d{9}$
      - name: Authorization
        in: header
        required: true
        schema:
          type: string
      - name: Gov-Client-Connection-Method
        in: header
        required: true
        schema:
          type: string
      - name: Gov-Vendor-Version
        in: header
        required: true
        schema:
          type: string
      requestBody:
        required: true
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/VatReturnRequest'
      responses:
        '201':
          description: VAT return accepted
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/VatReturnConfirmation'
        '400':
          description: Invalid VAT return data
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/Error'
        '403':
          description: Duplicate submission or period is closed
        '404':
          description: VRN not found
  /organisations/vat/{vrn}/returns/{periodKey}:
    get:
      operationId: getVatReturn
      summary: View a submitted VAT return
      description: Retrieves a previously submitted VAT return for the specified period key.
      tags:
      - Returns
      parameters:
      - name: vrn
        in: path
        required: true
        schema:
          type: string
          pattern: ^\d{9}$
      - name: periodKey
        in: path
        required: true
        schema:
          type: string
          pattern: ^\d{2}[A-Z]{2}$
        description: Period key from the obligation (e.g., "23AA")
      - name: Authorization
        in: header
        required: true
        schema:
          type: string
      responses:
        '200':
          description: VAT return retrieved
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/VatReturn'
        '404':
          description: Return not found
components:
  schemas:
    VatReturnRequest:
      type: object
      required:
      - periodKey
      - vatDueSales
      - vatDueAcquisitions
      - totalVatDue
      - vatReclaimedCurrPeriod
      - netVatDue
      - totalValueSalesExVAT
      - totalValuePurchasesExVAT
      - totalValueGoodsSuppliedExVAT
      - totalAcquisitionsExVAT
      - finalised
      properties:
        periodKey:
          type: string
          description: Period key matching an open obligation (e.g., "23AA")
        vatDueSales:
          type: number
          description: 'Box 1: VAT due on sales and other outputs'
        vatDueAcquisitions:
          type: number
          description: 'Box 2: VAT due on acquisitions from EC member states'
        totalVatDue:
          type: number
          description: 'Box 3: Total VAT due (Box 1 + Box 2)'
        vatReclaimedCurrPeriod:
          type: number
          description: 'Box 4: VAT reclaimed on purchases'
        netVatDue:
          type: number
          description: 'Box 5: Difference between Box 3 and Box 4'
        totalValueSalesExVAT:
          type: number
          description: 'Box 6: Total value of sales excluding VAT'
        totalValuePurchasesExVAT:
          type: number
          description: 'Box 7: Total value of purchases excluding VAT'
        totalValueGoodsSuppliedExVAT:
          type: number
          description: 'Box 8: Total value of goods supplied to EC member states (ex VAT)'
        totalAcquisitionsExVAT:
          type: number
          description: 'Box 9: Total acquisitions from EC member states (ex VAT)'
        finalised:
          type: boolean
          description: Declaration that the submission is a final return for the period
    VatReturnConfirmation:
      type: object
      properties:
        processingDate:
          type: string
          format: date-time
          description: Date and time HMRC received the VAT return
        formBundleNumber:
          type: string
          description: HMRC form bundle reference number (14 digits)
        paymentIndicator:
          type: string
          enum:
          - BANK
          - DD
          - CHAPS
          description: Preferred payment method held on HMRC record
        chargeRefNumber:
          type: string
          description: Charge reference number (if applicable)
    Error:
      type: object
      properties:
        code:
          type: string
          description: HMRC error code
        message:
          type: string
          description: Human-readable error description
        errors:
          type: array
          items:
            type: object
            properties:
              code:
                type: string
              message:
                type: string
              path:
                type: string
    VatReturn:
      allOf:
      - $ref: '#/components/schemas/VatReturnRequest'
      - type: object
        properties:
          periodKey:
            type: string
  securitySchemes:
    OAuth2UserRestricted:
      type: oauth2
      description: HMRC OAuth 2.0 Authorization Code grant (user-restricted)
      flows:
        authorizationCode:
          authorizationUrl: https://api.service.hmrc.gov.uk/oauth/authorize
          tokenUrl: https://api.service.hmrc.gov.uk/oauth/token
          scopes:
            write:vat: Submit VAT returns
            read:vat: Read VAT data
externalDocs:
  description: HMRC VAT API Documentation
  url: https://developer.service.hmrc.gov.uk/api-documentation/docs/api/service/vat-api/1.0