GovData Docs

Changelog

Notable changes to the GovData API.

Added

VAT Return Calculation API

  • New endpoint: POST /v1/tax/vat/return/calculate — full 9-box VAT return calculation
  • Standard VAT accounting with domestic sales, purchases, credit/debit notes, and journals
  • Flat Rate Scheme (FRS) with per-transaction percentages and capital goods reclaim
  • EC supplies and acquisitions (goods and services) with Box 2/8/9 derivation
  • Domestic Reverse Charge (DRC) and Postponed VAT Accounting (PVA)
  • Partial exemption: standard method, de minimis test, annual adjustment, special method passthrough
  • Bad debt relief with 6-month calendar month validation
  • HMRC fuel scale charge calculation by CO2 band and fuel type
  • 25 validation error codes with detailed messages
  • Breakdown detail levels: full, summary, or none
  • Scheme summary and rounding summary in every response
Added

Calendar API — Bank Holidays

  • New endpoint: GET /v1/calendar/bank-holidays — list all bank holidays
  • New endpoint: GET /v1/calendar/bank-holidays/:year — holidays by year
  • New endpoint: GET /v1/calendar/bank-holidays/next — next upcoming holiday per region
  • New endpoint: GET /v1/calendar/regions — list supported regions
  • Covers England & Wales, Scotland, and Northern Ireland
  • Automated weekly sync from GOV.UK bank holidays data
Added

Tax Years API

  • New endpoint: GET /v1/tax/years — list all tax years
  • New endpoint: GET /v1/tax/years/current — current active tax year
  • New endpoint: GET /v1/tax/years/:id — specific tax year details
  • Includes key dates: self-assessment deadline, payment on account dates, P60/P11D deadlines
Added

Take-Home Calculator

  • New endpoint: POST /v1/tax/take-home/calculate
  • Combined income tax + NI calculation in a single request
  • Returns net annual, monthly, and weekly pay
  • Includes marginal tax rate and employer NI costs
  • Supports England/Wales/NI and Scotland tax regions
Added

Income Tax & National Insurance APIs

  • New endpoint: GET /v1/tax/income/bands — income tax bands by region
  • New endpoint: POST /v1/tax/income/calculate — income tax calculation
  • New endpoint: GET /v1/tax/national-insurance/thresholds — NI thresholds
  • New endpoint: POST /v1/tax/national-insurance/calculate — NI calculation
  • Supports employed and self-employed NI calculations
  • Personal allowance taper for incomes over £100,000
Launch

GovData API v1 — Initial Release

  • API key authentication with test and live key support
  • Per-minute rate limiting and credits-based usage billing
  • Consistent JSON response format with data / meta envelope
  • All data sourced from official GOV.UK and HMRC publications