MTD Mandation Timeline — What Is Required When
| MTD Programme | Mandation Date | Who Is Affected | HMRC API Required |
|---|---|---|---|
| MTD for VAT | April 2022 (all VAT-registered) | All VAT-registered businesses (inc. voluntarily registered) | MTD VAT API (submit VAT returns digitally) |
| MTD for ITSA (Phase 1) | April 2026 | Self-employed and landlords with £50K+ annual income | MTD ITSA API (quarterly updates + annual declaration) |
| MTD for ITSA (Phase 2) | April 2027 | Self-employed and landlords with £30K+ annual income | MTD ITSA API |
| MTD for ITSA (Phase 3) | TBC (likely 2028) | Self-employed and landlords with under £30K annual income | MTD ITSA API |
| MTD for Corporation Tax | TBC — not before 2026 | Companies liable for UK Corporation Tax | MTD CT API (in development) |
| Bridging software | Available now | Businesses using spreadsheets — bridges to MTD | MTD VAT API via bridging software layer |
HMRC MTD API — Technical Integration
HMRC MTD APIs are available on the HMRC Developer Hub. All require OAuth 2.0 authentication (Government Gateway credentials). Key technical requirements:
API
Purpose
Key Endpoints
Authentication
MTD VAT
Submit VAT returns digitally
GET obligations, POST return, GET liabilities
OAuth 2.0 (user grants access to accounting software)
MTD ITSA
Quarterly business income/expenses
POST self-employment income, POST property income, GET obligations
OAuth 2.0 (individual or agent)
Agent Authorisation
Accountants submitting on behalf of clients
GET authorisation status, create invitation
OAuth 2.0 (agent credentials)
Business Income Source Summary
Annual income summary
GET, POST BISS
OAuth 2.0
MTD VAT Bridging
Spreadsheet bridge to MTD
GET/POST VAT return only
OAuth 2.0
Digital Links — The Key MTD Technical Requirement
Source data → accounting software: electronic import (CSV, API, direct connection) — not manual typing.
Between accounting systems: API integration or automated export/import — not copy-paste or manual transfer.
Accounting software → HMRC: direct API submission — not printing a return and re-entering it on the HMRC portal.
Spreadsheet + bridging software: permitted — but the link between the spreadsheet and the bridging software must be a digital link (automated import, not manual re-keying).
HMRC's digital links requirement: a "digital link" is an electronic transfer or exchange of data between software programs or between software and HMRC's system. No manual re-keying of data is permitted in the digital records chain. Implications for software development:
MTD Compatible Software — HMRC Recognition
Register on HMRC Developer Hub: create an account, agree to terms of use, access sandbox (test) environment.
Sandbox testing: test all required API endpoints in the HMRC sandbox environment with HMRC-provided test credentials.
Production application: apply for production credentials (HMRC reviews the application — typically 2–4 weeks).
MTD recognition: submit for inclusion on the HMRC-recognised MTD software list (separate application process).
HMRC maintains a list of MTD-compatible software products on GOV.UK. To achieve HMRC recognition as MTD-compatible: