AI2Fin GST & Tax API

openapi: 3.2.0
info:
  title: AI2Fin Financial Management GST & Tax API
  description: Financial management platform with AI-powered categorization, tax optimization, and bill management.
  version: 1.0.0
  contact:
    name: AI2Fin Support
    url: https://ai2fin.com
  license:
    name: Proprietary
servers:
- url: https://api.ai2fin.com
  description: Production
- url: http://localhost:3001
  description: Local Development
security:
- bearerAuth: []
- cookieAuth: []
tags:
- name: GST & Tax
  description: Global GST/VAT rate lookup and calculations
paths:
  /api/tax/country-rates:
    get:
      tags:
      - GST & Tax
      summary: List country tax rates
      description: Fetch all active tax rates grouped by country
      responses:
        '200':
          description: Tax rates retrieved
          content:
            application/json:
              schema:
                type: object
                properties:
                  success:
                    type: boolean
                  data:
                    type: object
                    properties:
                      rates:
                        type: array
                        items:
                          $ref: '#/components/schemas/TaxRate'
                      ratesByCountry:
                        type: object
                        additionalProperties:
                          type: array
                          items:
                            $ref: '#/components/schemas/TaxRate'
      operationId: getApiTaxCountryRates
      x-operation-id-source: derived
  /api/tax/rates/{countryCode}:
    get:
      tags:
      - GST & Tax
      summary: Get country tax rates
      description: Retrieve active tax rates for a specific country
      parameters:
      - name: countryCode
        in: path
        required: true
        schema:
          type: string
          example: AU
      responses:
        '200':
          description: Rates retrieved
          content:
            application/json:
              schema:
                type: object
                properties:
                  success:
                    type: boolean
                  data:
                    type: array
                    items:
                      $ref: '#/components/schemas/TaxRate'
        '404':
          description: Rates not found
      operationId: getApiTaxRatesByCountryCode
      x-operation-id-source: derived
  /api/tax/calculate:
    post:
      tags:
      - GST & Tax
      summary: Calculate GST/VAT
      description: Calculate GST/VAT amounts for tax-inclusive or tax-exclusive inputs
      requestBody:
        required: true
        content:
          application/json:
            schema:
              type: object
              required:
              - amount
              - gstIncluded
              properties:
                amount:
                  type: number
                gstIncluded:
                  type: boolean
                gstRate:
                  type: number
                  description: Optional rate override
                countryCode:
                  type: string
                  description: Fallback to lookup rate when provided
                taxType:
                  type: string
                  description: Tax type (GST, VAT, SALES_TAX, etc.)
      responses:
        '200':
          description: Calculation complete
          content:
            application/json:
              schema:
                type: object
                properties:
                  success:
                    type: boolean
                  data:
                    $ref: '#/components/schemas/TaxCalculationResult'
      operationId: postApiTaxCalculate
      x-operation-id-source: derived
components:
  schemas:
    TaxCalculationResult:
      type: object
      properties:
        amount:
          type: number
        baseAmount:
          type: number
        gstAmount:
          type: number
        gstIncluded:
          type: boolean
        gstRate:
          type: number
        input:
          type: object
          properties:
            amount:
              type: number
            gstIncluded:
              type: boolean
            gstRate:
              type: number
            countryCode:
              type: string
            taxType:
              type: string
    TaxRate:
      type: object
      properties:
        countryCode:
          type: string
        taxType:
          type: string
        taxName:
          type: string
        standardRate:
          type: number
        reducedRate:
          type:
          - number
          - 'null'
        zeroRate:
          type: number
        combinedRate:
          type:
          - number
          - 'null'
        stateProvince:
          type:
          - string
          - 'null'
        description:
          type:
          - string
          - 'null'
  securitySchemes:
    bearerAuth:
      type: http
      scheme: bearer
      bearerFormat: JWT
      description: First-party access token for your own signed-in session, obtained from the /api/enterprise-auth/login endpoint. The REST API returns your own account data to you — it is a first-party consumer surface, not a third-party integration channel. Data from connected bank feeds (open-banking / CDR data) is your own data, returned only to you in your own authenticated session.
    cookieAuth:
      type: apiKey
      in: cookie
      name: ai2_sess
      description: Session cookie for web applications
    apiKeyAuth:
      type: apiKey
      in: header
      name: X-API-Key
      description: 'API key for the MCP Inspector endpoint (/mcp/inspector) only. Generate your own key via /api/api-keys. Format: mcp_<64 hex characters>. API keys carry mcp:* scopes and authenticate MCP Inspector operations — they are not accepted on the REST API (/api/...) or the main MCP endpoint (/mcp), which use OAuth bearer tokens.'