Dated, non-normative product research. This is not legal or tax advice and not part of YUTABASE conformance. Reverify time-sensitive claims against current primary sources before acting.
Mapped 2026-07-09 by Fable, at Yu’s ask. Every load-bearing number below is verified to legislation or a GOV.UK/HMRC page; sources inline. The product inventory is from a full mirror of the live site taken the same day. Companion doctrine: TAXSORTED.md.
780,000 people were mandated into MTD Income Tax three months ago; barely 28% had signed up by April. The first quarterly deadline in UK history is 7 August 2026. Every listed competitor charges £10–33/month or gates “free” behind a bank account or caps. HMRC officially encourages free software — and no open-source product has ever been recognised. The door is open, and the clock is ticking in our favour.
The three waves — made law, not proposals. Regulation 27 of the Income Tax (Digital Obligations) Regulations 2026 (SI 2026/336, in force 1 Apr 2026, replacing the never-commenced 2021/2024 regs):
| From | Qualifying income over | Base year | People |
|---|---|---|---|
| 6 Apr 2026 | £50,000 | 2024-25 return | ~780,000 |
| 6 Apr 2027 | £30,000 | 2025-26 return | ~900,000 more |
| 6 Apr 2028 | £20,000 | 2026-27 “and subsequent” | ~970,000 more |
≈ 2.65M mandated by 2028; the ~4M below £20k are “continue to assess” — possible but unscheduled this Parliament.
Qualifying income = total gross self-employment + property income (turnover/rents, before expenses), from the prior-prior year’s SA return; includes your share of joint property; excludes PAYE, dividends, partnership shares, pensions, savings, REIT/PAIF, qualifying-care receipts, transition profits. (GOV.UK)
The three obligations (use-MTD guidance):
Exemptions (automatic): partnerships (no mandation date set at all), trusts (SA900), non-resident companies, personal representatives, income ≤ £20k, no NINO by tax-year start (exempt that year), incapacity with PoA/deputy, Lloyd’s underwriters, ministers of religion, MCA/BPA claimants. Temporary until ≥ Apr 2027: averaging claims (farmers/creatives), qualifying care relief, SA107, SA109. By application: digital exclusion (age/health/religion/location; not cost or unfamiliarity; ~28-day decision; can be permanent).
Penalties (GOV.UK):
The eight Minimum Functionality Standards APIs (all must be met, alone or via digitally-linked combination — end-to-end guide):
| API | Version | Role |
|---|---|---|
| Business Details | v2.0 | list income sources, business IDs, quarter-type election |
| Obligations | v3.0 | income & expenditure + final-declaration obligations |
| Self-Employment Business | v5.0 | cumulative update: PUT …/self-employment/{nino}/{businessId}/cumulative/{taxYear} |
| Property Business | v6.0 | cumulative property updates |
| Business Source Adjustable Summary | v7.0 | year-end accounting adjustments |
| Individual Calculations | v8.0 | trigger/retrieve calc + submit the final declaration |
| Individual Losses | — | loss claims |
| Individuals Tax Liability Adjustments | — | liability adjustments |
The End of Period Statement is abolished (gone from the API index). Year-end journey = BSAS adjustments → trigger calc → retrieve → submit declaration.
Auth: OAuth 2.0 authorization-code, scopes read/write:self-assessment;
access tokens 4h; refresh tokens 18 months, single-use rotating. Sandbox at
test-api.service.hmrc.gov.uk with Government Gateway test users (Create
Test User API for automation).
Fraud prevention headers: required by law (SI 2019/360) for all ITSA
MTD APIs; the required set depends on Gov-Client-Connection-Method (ours:
WEB_APP_VIA_SERVER); compliance is checked before production access.
Omission route exists via SDSTeam@hmrc.gov.uk. The site already documents
all 16 headers and has drafts for the two we can’t send — unsent.
The recognition path (self-serve since 17 Jun 2024 — no live demo): register app → sandbox test users → build → Production Approvals Checklist → production credentials → optional “in development” listing → live-submission proof → per-feature “Ready now” listing in the software finder (features are labelled Ready now / In development / Not included).
The open goal: HMRC “strongly encourages all software providers to produce a free version”; the government is “committed to ensuring the availability of free software products for small businesses with simple tax affairs”. The recognised list (~20-40 products) has no open-source product, ever. Free options are conditional (FreeAgent: NatWest/RBS account), capped (QuickFile 1,000 entries; Sage sole-trader-free: no landlords), or niche. Paid entry tiers: QuickBooks £10, Xero ~£15-16, FreeAgent £10-33. A genuinely free, open-source, no-account, full-journey product would be the first of its kind on the list.
Standing — landing (ledger design + whole-site theme layer); ITSA toolkit: Am I in? checker · Your records (browser-local) · Quarterly figures & estimate · ITSA cockpit (deadline, penalty position incl. the 26-27 easement, cited £ estimate); Learn: MTD-don’t-panic · Income Tax (2026-27 bands, taper trap) · Self-employed (simplified expenses) · Landlords (FHL abolition) · the gov series ×5 (how law is made · who runs your taxes · your levers · receipts · what-we-send-HMRC with all 16 fraud headers documented and two honest omissions drafted); the tax game + deep politics; VAT sample-books preview; i18n ×5 (EN/繁·廣/简/PL/HI).
Not yet standing — OAuth connect; any real HMRC API call; production credentials; software-finder listing; Account is a stub; mileage minimal.
WEB_APP_VIA_SERVER.Learn-only page; thesis: 有啲地圖細,係因為真相簡單 — “Some maps are small because the truth is small.” (The joke in TAXSORTED.md, made real, Cantonese first.)
The map renders only what is true. The gaps are stated, never silent. — Fable, 2026-07-09