openapi: 3.0.0
info:
  title: Fonoa Tax Engine API
  description: >
    Tax calculation API that determines applicable VAT, GST, and sales tax rates for
    transactions across 100+ jurisdictions. Supports B2C and marketplace scenarios with
    real-time tax determination and the ability to view and commit calculations.
  contact:
    name: Fonoa Support
    url: https://www.fonoa.com/
    email: support@fonoa.com
  version: '1.0'
servers:
  - url: https://api-demo.fonoa.com
    description: Fonoa API demo environment
  - url: https://sandbox.fonoa.com/
    description: Fonoa API sandbox environment
  - url: https://api.fonoa.com
    description: Fonoa API production (live) environment
paths:
  /tax/v2/calculations:
    post:
      summary: Request a calculation
      description: >
        In the one example, you can see a tax determination for a service provided directly
        to a consumer not through a marketplace. The other example shows a tax determination
        for a transaction that takes place between a third party seller and a consumer through
        a marketplace.
      operationId: Requestataxrate
      tags:
        - Tax
      requestBody:
        content:
          application/json:
            schema:
              $ref: '#/components/schemas/TaxDetermineRequest'
            examples:
              marketplace_transaction:
                summary: Marketplace transaction
                value:
                  supplier:
                    taxable: true
                    country: ca
                    tax_region: bc
                    registered_in_customer_country: true
                    reference_id: supplier123
                  customer:
                    taxable: true
                    country: it
                  marketplace:
                    registered_in_customer_country: true
                    calculate_for_unregistered_customer_countries: true
                    is_user_marketplace: true
                  transaction:
                    id: order7898
                    price_includes_tax: true
                    date: '2022-06-15T13:40:31+10:00'
                    description: a transaction for a digital service
                    through_marketplace: true
                    items:
                      - id: '1'
                        unit_price: 100
                        tax_category_code: fs_0302003000
                        quantity: 1
                        description: a digital service
              direct_sale:
                summary: Direct sale example (non-marketplace)
                value:
                  supplier:
                    taxable: true
                    country: us
                    registered_in_customer_country: true
                  customer:
                    taxable: false
                    country: ro
                  transaction:
                    price_includes_tax: true
                    date: '2022-06-20T13:12:31+08:00'
                    items:
                      - id: '1'
                        unit_price: 100
                        tax_category_code: fs_0302003000
                        quantity: 1
                        description: an electronic service
      responses:
        '200':
          description: OK
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/TaxDetermineResponse'
        '400':
          description: Bad Request
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/TaxDetermineResponseError'
        '500':
          description: Internal Server Error
          content:
            application/json:
              schema:
                $ref: '#/components/schemas/TaxDetermineResponseError'
components:
  schemas:
    TaxDetermineRequest:
      type: object
      title: TaxCalculatePOSTrequest
      required:
        - supplier
        - customer
        - transaction
      properties:
        supplier:
          type: object
          description: The supplier object contains parameters related to the supplier/seller for a given transaction.
          required:
            - taxable
            - country
          properties:
            taxable:
              type: boolean
              description: Defines whether the supplier is taxable or not in the supplier country.
            country:
              type: string
              minLength: 1
              description: Supplier's country code expressed in ISO 3166-1 alpha-2 format.
              example: ca
            tax_region:
              type: string
              description: Supplier's region code (e.g., bc for British Columbia).
              example: bc
            registered_in_customer_country:
              type: boolean
              description: Specifies whether the supplier is tax registered in the customer country.
            reference_id:
              type: string
              description: Unique identifier for a third-party supplier in marketplace scenarios.
              example: supplier123
        customer:
          type: object
          description: The customer object contains parameters related to the customer/buyer for a given transaction.
          required:
            - taxable
            - country
          properties:
            taxable:
              type: boolean
              description: Defines whether the customer is taxable or not in the customer country.
            country:
              type: string
              minLength: 1
              description: Customer's country code expressed in ISO 3166-1 alpha-2 format.
              example: it
            tax_region:
              type: string
              description: Customer's region code. Only relevant for certain countries.
        marketplace:
          type: object
          description: Parameters related to the marketplace for marketplace transactions.
          properties:
            registered_in_customer_country:
              type: boolean
              description: Indicates whether the marketplace is tax registered in the customer country.
            calculate_for_unregistered_customer_countries:
              type: boolean
              description: Whether to receive a calculation even if not registered in the customer country.
            is_user_marketplace:
              type: boolean
              description: Indicates whether a transaction is processed from a marketplace's perspective.
        transaction:
          type: object
          description: Parameters related to the order/transaction in general.
          required:
            - date
            - items
          properties:
            id:
              type: string
              minLength: 1
              maxLength: 36
              description: Unique identifier for the transaction.
              example: order7898
            price_includes_tax:
              type: boolean
              description: Specifies whether the prices include indirect taxes.
              default: true
            date:
              type: string
              format: date-time
              description: Date of the transaction in ISO8601 format.
              example: '2022-06-15T13:40:31+10:00'
            description:
              type: string
              maxLength: 128
              description: Description for the transaction.
              example: a transaction for a digital service
            through_marketplace:
              type: boolean
              description: Specifies whether the transaction takes place through a marketplace.
            items:
              type: array
              uniqueItems: true
              minItems: 1
              description: Items being transacted with their details.
              items:
                type: object
                required:
                  - id
                  - unit_price
                  - tax_category_code
                properties:
                  id:
                    type: string
                    minLength: 1
                    maxLength: 32
                    description: Unique id per line item.
                    example: '1'
                  unit_price:
                    type: number
                    description: Item amount/value.
                    exclusiveMinimum: true
                    minimum: 0
                    example: 100
                  tax_category_code:
                    type: string
                    minLength: 1
                    description: Code specifying the category of the item being transacted.
                    example: fs_0302003000
                  quantity:
                    type: number
                    minimum: 1
                    default: 1
                    description: Quantity for this line item.
                  description:
                    type: string
                    maxLength: 128
                    description: Description for the line item.
                    example: a digital service
    TaxDetermineResponse:
      type: object
      required:
        - total_gross
        - total_net
        - total_indirect_tax_amount
        - items
      properties:
        total_gross:
          type: number
          description: The gross amount of the entire transaction excluding withholding taxes.
        total_net:
          type: number
          description: The net amount of the entire transaction.
        total_indirect_tax_amount:
          type: number
          description: The aggregation of all indirect tax amounts for the transaction.
        items:
          type: array
          uniqueItems: true
          minItems: 1
          description: Tax breakdown per item in the transaction.
          items:
            type: object
            required:
              - id
              - unit_price
              - gross_amount
              - net_amount
              - indirect_tax_amount
              - effective_indirect_tax_rate
              - tax_breakdown
            properties:
              id:
                type: string
                minLength: 1
                description: The id provided in the API request for this item.
              quantity:
                type: integer
                description: The quantity provided in the API request for this item.
              unit_price:
                type: number
                format: float
                description: The unit_price provided in the API request for this item.
              supplier_taxable:
                type: boolean
                description: Whether the supplier is taxable.
              tax_logic_label:
                type: string
                description: A string identifying the tax logic applied for that transaction.
              gross_amount:
                type: number
                description: Gross amount for the item multiplied by quantity.
              net_amount:
                type: number
                description: Net amount for the item stripped of indirect taxes.
              indirect_tax_amount:
                type: number
                description: Aggregation of tax amounts from all indirect taxes applied.
              effective_indirect_tax_rate:
                type: number
                description: Effective indirect tax rate for the item.
              unit:
                type: object
                description: Gross, net, and indirect tax amounts at unit level (quantity=1).
                properties:
                  net_amount:
                    type: number
                  gross_amount:
                    type: number
                  indirect_tax_amount:
                    type: number
              tax_breakdown:
                type: array
                description: Detailed taxes that apply for this item.
                items:
                  type: object
                  required:
                    - type
                    - name
                    - amount
                    - rate
                    - remit
                    - country
                    - tax_region
                  properties:
                    type:
                      type: string
                      description: Type of tax applied (indirect or withholding).
                      example: indirect
                    name:
                      type: string
                      description: Specific name of the tax applied.
                      example: IVA
                    amount:
                      type: number
                      description: Tax amount applied, multiplied by quantity.
                      example: 20
                    rate:
                      type: number
                      description: Tax rate applied.
                      example: 0.25
                    remit:
                      type: number
                      description: Amount to be remitted to the government.
                      example: 20
                    country:
                      type: string
                      description: Country of the applied tax in ISO 3166-1 alpha-2 format.
                      example: ca
                    tax_region:
                      type: string
                      description: Tax region of the applied tax.
                      example: on
                    taxable_amount:
                      type: number
                      description: Amount on which the tax was applied.
                      example: 80
    TaxDetermineResponseError:
      title: TaxCalculateResponseError
      type: object
      properties:
        errors:
          type: array
          items:
            type: object
            properties:
              type:
                type: string
              message:
                type: string
              field:
                type: string
  securitySchemes:
    Ocp-Apim-Subscription-Key:
      type: apiKey
      description: API Subscription Key
      name: Ocp-Apim-Subscription-Key
      in: header
security:
  - Ocp-Apim-Subscription-Key: []
tags:
  - name: Tax