The thesis in one paragraph. 2.179m UK businesses are VAT-registered. MTD VAT has been mandatory for all of them since April 2022. The basic-filing market is commoditised at £14–£33/mo (Xero / Sage / QuickBooks). What's not commoditised — partial exemption, reverse charge / DRC, margin schemes, OSS / IOSS, place-of-supply, postponed VAT accounting, capital goods scheme, TOMS, group VAT, HMRC enquiry response, the post-Jan-2023 points-based penalty regime — is where SMEs systematically overpay, under-claim or get penalised. That's where vat.law lives.
Documents
CLAUDE.md
Session rules · regulatory architecture · pricing · session rules. Read first.
STRATEGY.html
Research → react → build pattern · market data · the gap · exit comparables.
TECH_REUSE_BLUEPRINT.html
78% Supreme-stack reuse audit · 4-week £5,600 build plan.
PRODUCT_SPEC.html
User journeys · feature spec · DB schema · API surface.
BUILD_PLAN.html
4-week sprint · risk register · gating criteria.
LANDING_PAGE.html
Customer-facing landing page · vat.law/.
RUNTIME_DASHBOARD.html
Operational view of the live runtime · penalty-point heatmap · enquiry queue.
CLAUDE_PROJECT_SETUP.md
Claude Project setup · 7 India team prompts · CTA partner protocol.
DEVELOPER_PACK/INDEX.html
21-file snap pack · SQL · modules · templates · workflows · railway · manifest.
The numbers
| Metric | Value | Source / status |
|---|---|---|
| UK VAT-registered businesses | 2.179m | HMRC · data.gov.uk |
| MTD VAT mandatory since | April 2022 | HMRC · no threshold opt-out |
| New points-based penalty regime live | 1 Jan 2023 | HMRC · 4 pts → £200 fixed |
| Late-payment penalty escalation | April 2025 | LPP1 3%+3% · LPP2 10% pa daily |
| HMRC predicted MTD yield | £4bn+ | HMRC June 2025 tax gap report |
| Productivity gain from MTD (HMRC research) | 22% | 73% saw no change · HMRC research |
| HMRC's own cost of collecting VAT post-MTD | +15% | TaxWatchUK |
| Stack reuse from existing OS verticals | 78% | sole.tax 95% · accounts.law 60% · form.law 95% |
| Build cost | £5,600 | 4 weeks · 1 founder + 1 India dev rotation |
| Y1 revenue target | £481k | Subs £408k + enquiry £40k + annual uplift £25k + SC £8k |
| Y5 ARR target | £4–6m | 4,000+ Pro-and-above customers |
| Exit comp zone | £40–80m | Avalara $8.4B · Vertex listed · Sovos PE-backed |
Pricing
| Tier | Price | Customer |
|---|---|---|
| Essentials | £19 / mo | Sole trader / micro · simple turnover · already on Xero/Sage but wants penalty-point tracker + error checker |
| Pro | £49 / mo | Construction / hospitality / retail · DRC · margin schemes · partial exemption · capital goods · cash-accounting optimisation |
| Cross-Border | £149 / mo | E-commerce / SaaS / wholesale · OSS / IOSS · place-of-supply · postponed VAT accounting · EORI · group VAT · TOMS |
| HMRC enquiry response | £495 one-off | Any tier · standalone · audit-trail extraction · trained QA reviewer + CTA partner · Supreme Capital advance financing referral |
What makes this build cheap
vat.law is the 25th deployment off the Supreme Operating System. The MTD HMRC API plumbing already exists in sole.tax (Vertical #7) — OAuth, obligation poll, 9-box submission, digital-link audit. The cron pattern (90/60/30/7-day exposure alerts) already exists in pension.law. The doc factory already exists in apex.studio. The CTA partner-network architecture is a direct copy of the OISC partner pattern from immigration.law (Vertical #24, built yesterday). Net-new work is the complex-VAT calculation modules (partial exemption · DRC · margin · place-of-supply · TOMS · capital goods) and the HMRC enquiry response workflow.