QuarterFile
MTD for Income Tax starts April 6. QuarterFile reads your bank statements, auto-categorises every transaction, and produces an HMRC-ready quarterly return in under 5 minutes.
The Idea
Making Tax Digital for Income Tax Self Assessment (MTD ITSA) becomes mandatory on 6 April 2026 for sole traders and landlords earning over £50,000 per year. That's roughly 700,000 people in the first wave. Instead of one annual self-assessment return, they now have to submit quarterly digital updates to HMRC, plus a final declaration at year end. Every submission requires HMRC-compatible software: you cannot submit through the standard HMRC online account anymore. QuarterFile eliminates the pain. Upload a bank statement PDF or CSV export, and the AI categorises every transaction into the correct HMRC expense categories, flags anything ambiguous for your review, and outputs a clean quarterly summary in the exact format required for submission. No accounting software subscription. No accountant at £150 per hour. Just £29 per quarter.
Why Now
The mandate starts in 7 days. April 6, 2026 is the hard legal deadline for the first wave of affected taxpayers. HMRC's own guidance states clearly that "you cannot use your HMRC online account to submit" quarterly updates: you must use compatible software. The existing options are either too complex (Xero, QuickBooks at £30 or more per month) or too locked-in (SumUp's free tool only works if you already use SumUp). Every financial journalist in the UK has covered this deadline. Search volume for "MTD ITSA software" and "Making Tax Digital sole trader 2026" spiked sharply this month. The urgency wave is cresting. The April 2027 expansion to cover anyone earning over £30,000 brings in another 1.3 million people, meaning the market more than doubles with zero additional build cost.
How to Build
Bank statement input: accept PDF exports from major UK banks (Barclays, Monzo, Starling, HSBC, Lloyds) and CSV exports from any bank or accounting tool. Use Claude to parse and categorise each transaction into the HMRC allowable expense sub-categories: office costs, travel, stock and materials, financial charges, professional fees, advertising, clothing (uniforms only), and staff costs. Build a clean review UI: every AI-categorised transaction in a simple table, with one-click overrides for anything flagged as uncertain. Output a formatted quarterly update summary mapping exactly to the HMRC MTD ITSA data requirements. For actual submission in V1, produce a clean import file for Sage Individual (free, HMRC-recognised) or equivalent bridge tool. V2 targets direct HMRC API recognition. Stack: Next.js, Vercel, Stripe, Claude API.
Revenue Model
£29 per quarter per user, billed as needed (4 submissions per year = £116/year). Annual flat rate at £89 for early adopters, which removes any friction around billing timing. The price anchors directly against a bookkeeper at £50-150 per hour, or the ongoing cost of a full accounting suite most sole traders do not need. Target the first wave of 700,000 affected taxpayers at a 0.5% conversion rate: 3,500 users at £89/year = £311,500 ARR before the April 2027 cohort even kicks in. Accountant referral channel: accountants who currently handle MTD for their simpler clients as a time-consuming admin task will happily refer those clients to an £89/year tool rather than billing them at hourly rates for a 15-minute job.
Effort
1 week to a usable v1. Day 1-2: bank statement parsing pipeline, tested against 10 real exports from the major UK banks. Day 3: Claude categorisation prompt, calibrated against HMRC's eight allowable expense categories and validated against GOV.UK's own published guidance. Day 4: review UI and transaction override interface. Day 5: quarterly summary output, formatted for import into Sage Individual or equivalent. Day 6: Stripe checkout and basic user accounts. Day 7: landing page and distribution push targeting "MTD ITSA software April 2026" search traffic and freelancer communities (r/freelanceuk, Freelancer Forum, IPSE members). The HMRC direct API recognition path is V2: the initial version is honest about being a prep layer that feeds into a recognised tool, which is still genuinely useful and avoids a certification bottleneck.
Risk
Two real risks. First, HMRC API certification: direct digital submission requires software recognition from HMRC, a process that takes months. V1 must be framed clearly as a preparation and categorisation tool that outputs a file ready for any recognised bridge tool, not a direct submission service. That is still valuable: the categorisation and quarterly summary generation is the hard part, not the final submission click. Second, data sensitivity. Sole traders uploading full bank statements is a significant privacy ask. Airtight data handling, a clear deletion policy, and a prominent "we do not store your raw bank data after processing" message are non-negotiable before the first upload screen. Get the privacy messaging right and it becomes a selling point, not a blocker.
The April 6 deadline is 7 days away and 700,000 sole traders are scrambling to find software that isn't a full accounting suite. The existing options are complex, expensive, or locked behind proprietary payment platforms. A bank-statement-in, quarterly-report-out workflow is exactly what this market needs, and nobody has built it cleanly for the non-accountant sole trader. The April 2027 expansion to the £30,000 income threshold means the window stays open and grows. Build the prep layer first, earn the HMRC recognition second. The urgency is doing your marketing for you.