Building ClearMTD: Making Tax Digital, Made Simple

From April 2026, self-employed individuals and landlords earning over £50,000 must comply with Making Tax Digital for Income Tax. From April 2027, the threshold drops to £30,000. This isn't optional — it's law.

The existing software options were either overpriced, bloated with features nobody asked for, or both. So we built ClearMTD: a focused, affordable tool that does one thing well — MTD compliance. Here's the story.

The Problem

Making Tax Digital for Income Tax requires sole traders and landlords to:

• Keep digital records of all business income and expenses
• Submit quarterly updates to HMRC (four times a year, not just once)
• File a Final Declaration at the end of the tax year

The software market wasn't ready for this. The big players — Xero, QuickBooks, Sage — all support MTD, but they come loaded with invoicing, payroll, bank feeds, and project management that a sole trader or landlord simply doesn't need. And they charge £12–25+ per month for the privilege.

On the other end, free spreadsheet approaches don't meet HMRC's digital linking requirements. There was a clear gap: affordable, focused MTD software that does what's needed and nothing more.

The Founder's Perspective

ClearMTD was built by Steven Hallissey FCA — a Fellow of the Institute of Chartered Accountants in England and Wales with 26 years of experience as a CFO and Finance Director across technology, financial services, and professional services.

That background matters. Understanding tax compliance isn't just about building software — it's about knowing exactly what HMRC requires, what records need to be kept, and where businesses get tripped up. ClearMTD was designed by someone who's lived this world, not by a startup guessing at it.

What ClearMTD Does

Connect to HMRC

Users securely link their HMRC account via OAuth — the same authentication standard used by banks. One click, no manual credentials. ClearMTD pulls the user's obligation periods directly from HMRC, so they always know what's due and when.

Enter Your Numbers

Simple forms for income and expenses. No accounting jargon, no chart of accounts, no double-entry bookkeeping. Enter what you earned and what you spent. ClearMTD handles the rest.

Submit to HMRC

One-click submission. ClearMTD formats the data, sends it to HMRC via their official MTD API, and confirms the submission. After filing, users see their calculated tax liability — income tax, National Insurance contributions, and total due.

Free MTD Checker

Not sure if MTD applies to you? The MTD Checker tool on the homepage asks a few simple questions and tells you whether you need to comply, which threshold applies, and when your first submission is due. No signup required.

Agent Portal

Accountants managing multiple clients can use the agent portal to handle submissions on their behalf. One login, multiple client businesses, centralised filing.

The Differentiator

ClearMTD does one thing well. No invoicing. No payroll. No bank feeds. No project management. Just digital records and HMRC submissions.

That focus keeps the product simple and the price low:

• £7.50/month or £65/year (saves 28%)
• Competitors charge £12–25+ per month for features you'll never use
• Sign up free — no payment required until you submit to HMRC
• Cancel anytime

Setup takes minutes, not hours. There's no chart of accounts to configure, no integrations to set up, and no training videos to watch.

The Tech Stack

ClearMTD is built with the same modern stack we use across all SH Applications products:

• FastAPI for the backend — async Python web framework, fast and well-documented
• PostgreSQL for the database — managed on Render, with Alembic migrations
• HTMX for the frontend — server-rendered HTML with dynamic interactions, no JavaScript framework needed
• Stripe for billing — subscription management with webhook-driven activation
• HMRC MTD API for tax submissions — custom OAuth 2.0 client with token refresh, obligation polling, and submission handling

The HMRC API integration was the most complex piece. HMRC's sandbox environment, OAuth flow, fraud prevention headers, and obligation endpoint all required careful implementation and testing. The result is a reliable, production-grade connection that handles token expiry, error states, and edge cases gracefully.

Content as a Growth Engine

ClearMTD launched with 47 published blog articles covering every aspect of Making Tax Digital — from "What is MTD?" basics to detailed guides for specific audiences (sole traders, landlords, gig workers, overseas property owners), expense categories, penalty rules, and software comparisons.

This wasn't an afterthought. The content strategy was planned before the first line of code was written. Each article targets a specific search intent, links internally to related guides, and funnels readers towards the product. The result is organic visibility from day one, not months of waiting for SEO to kick in.

What We Learned

• Government APIs are different. HMRC's API has strict requirements around fraud prevention headers, OAuth scopes, and sandbox vs production environments. Budget extra time for compliance testing and the approval process.
• Simplicity is the feature. Every feature we didn't build made the product better. Users don't want another accounting platform — they want to file their quarterly returns and get on with their day.
• Content compounds. 47 articles at launch means 47 pages competing for search traffic from day one. This gives ClearMTD a head start that competitors launching with a homepage and a pricing page simply can't match.
• Build for the mandate. MTD compliance isn't optional. The addressable market is every UK sole trader and landlord above the threshold. When the law requires your product, your marketing job is to make sure people know you exist.

The Result

ClearMTD is live at clearmtd.co.uk — a focused, affordable MTD compliance tool that UK sole traders and landlords can set up in minutes and use to stay on the right side of HMRC.

It demonstrates what SH Applications does best: take a real business problem, strip away the unnecessary complexity, and build something that works. ClearMTD was built from scratch — HMRC API integration, Stripe billing, 47 blog articles, 110 passing tests — and shipped as a production-grade SaaS product.