> ## Documentation Index > Fetch the complete documentation index at: https://docs.flowpayroll.ai/llms.txt > Use this file to discover all available pages before exploring further. # Get the effective tax code and NI category for an employee on a specific date ## OpenAPI ````yaml /api-reference/specs/pay-api.yaml get /employees/{employeeId}/effective-tax-info openapi: 3.0.3 info: title: FlowPayroll API description: >- API for payroll management, including payroll upload, lock, HMRC submission, employee management version: 0.1.0 servers: - url: https://api.sandbox.flowpayroll.ai/v1 security: - XAuthToken: [] XOrgId: [] tags: - name: Employees description: >- Create, retrieve, update, and delete employee records, and look them up by NI number or payroll ID. - name: Starters & leavers description: Set and clear starter and leaver details, individually or in bulk. - name: Tax codes description: >- Manage employee tax codes and query the effective tax code and NI category on a given date. - name: NI & identifiers description: Manage NI categories, National Insurance numbers, and payroll IDs. - name: Student loans description: Start and end student and postgraduate loans. - name: Payroll setup description: Assign an employee's payroll config and set opening balances. - name: Payroll - name: Payroll lines - name: PayrollConfig - name: Pay Elements - name: Calculator - name: Payslip - name: RTI - name: YearEnd - name: Organisation paths: /employees/{employeeId}/effective-tax-info: get: tags: - Tax codes summary: >- Get the effective tax code and NI category for an employee on a specific date operationId: GetEffectiveTaxInfo parameters: - name: employeeId in: path required: true schema: type: string description: The ID of the employee - name: date in: query required: false schema: type: string format: date description: >- The date to get effective tax info for (YYYY-MM-DD). Defaults to today if not provided. responses: '200': description: Effective tax info retrieved successfully content: application/json: schema: type: object allOf: - $ref: '#/components/schemas/ResponseBody' - properties: content: type: object properties: data: $ref: '#/components/schemas/EffectiveTaxInfoDto' '400': description: Invalid date format content: application/json: schema: $ref: '#/components/schemas/ResponseBody' '404': description: Employee not found content: application/json: schema: $ref: '#/components/schemas/ResponseBody' '500': description: An internal server error occurred content: application/json: schema: $ref: '#/components/schemas/ResponseBody' components: schemas: ResponseBody: type: object properties: message: $ref: '#/components/schemas/MessageWithTokenResponse' content: type: object properties: data: type: object nullable: true metadata: type: object nullable: true properties: dateFormat: type: string default: yyyy-MM-dd dateTimeFormat: type: string default: yyyy-MM-ddTHH:mm:ss.fffZ paginationToken: type: string nullable: true validationIssues: type: array items: $ref: '#/components/schemas/ValidationIssue' messageToken: type: string EffectiveTaxInfoDto: type: object description: >- Response containing the effective tax code and NI category for a specific date required: - effectiveTaxCode - effectiveNiCategory - effectiveDate - taxYear properties: effectiveTaxCode: $ref: '#/components/schemas/EmployeeTaxCodeDto' effectiveNiCategory: $ref: '#/components/schemas/EmployeeNiCategoryDto' effectiveDate: type: string format: date description: The date for which the effective values were calculated example: '2024-06-15' taxYear: type: integer description: The tax year for which the effective values were calculated example: 2024 example: effectiveTaxCode: code: 1257L effectiveDate: '2024-04-06' reason: Annual Review issuedBy: HMRC week1Month1: false effectiveNiCategory: category: A effectiveDate: '2024-04-06' reason: Annual Review issuedBy: HMRC effectiveDate: '2024-06-15' taxYear: 2024 MessageWithTokenResponse: type: object properties: text: type: string token: type: string tokenArguments: type: array items: $ref: '#/components/schemas/ValidationIssueArgument' ValidationIssue: type: object description: > Field validation item. `reasonToken` is a stable snake_case key for i18n or custom client messages; `reason` is the default English text from the API. properties: field: type: string description: Dot-path of the field (e.g. name.firstName, address.line1). reason: type: string description: Default human-readable message. reasonToken: type: string description: Machine-readable error identifier (snake_case). reasonTokenArguments: type: array nullable: true items: $ref: '#/components/schemas/ValidationIssueArgument' EmployeeTaxCodeDto: type: object required: - code properties: code: type: string description: The tax code for the employee. example: 1257L effectiveDate: type: string nullable: true description: >- The effective date of the tax code, if none is set, created date is used. example: '2024-04-06' reason: type: string description: Reason for the tax code change example: Standard tax code issuedBy: type: string description: 'Who issued the tax code change. Valid values: ''HMRC'', ''Employer''' example: HMRC week1Month1: type: boolean description: Whether the tax code is week1Month1, meaning basis non cumulative example: false EmployeeNiCategoryDto: type: object required: - category - effectiveDate - reason - issuedBy properties: category: type: string description: HMRC-published NI category letter for payroll submissions. example: A enum: - A - B - C - D - E - F - H - I - J - K - L - M - 'N' - S - V - X - Z effectiveDate: type: string format: date description: Date when this category becomes effective example: '2025-04-06' reason: type: string description: Reason for the category example: HMRC Update issuedBy: type: string description: 'Who issued the category. Valid values: ''HMRC'', ''Employer''' example: HMRC ValidationIssueArgument: type: object properties: name: type: string value: type: string securitySchemes: XAuthToken: type: apiKey in: header name: X-Auth-Token description: Access token obtained from OAuth2 client credentials flow XOrgId: type: apiKey in: header name: X-Org-Id description: >- Organisation to scope the request to. Required when the principal can access more than one organisation; optional for single-organisation principals (the authorizer resolves it automatically). ````