Why Automate Taxes?

Marcus Tettmar
Published in
3 min readNov 11, 2019


I’m Marcus, I’m CTO at untied, and I know what it’s like doing taxes and dealing with HMRC.

Five years ago, the EU introduced new VAT rules for digital products. My business at the time sold automation software to people all over the world. The new rules required us to implement a new system for tracking the location of customers and determining the correct VAT rate to charge on our website. The new rules also required us to add something called VATMOSS to our VAT account with HMRC.

I was having a problem trying to add the service via HMRC’s website, so, with trepidation, I phoned them. The experience with their automated phone system was frustrating to say the least, but I also saw the funny side, so I phoned back and recorded the exchange. The end result went somewhat viral on YouTube:

A few days later I got a phone call from the producer of BBC Radio 4’s Moneybox programme, hosted by Paul Lewis (@paullewismoney). They’d heard my recording and were also planning a feature on the new EU VAT rules and how many small businesses were struggling with them. They invited me onto the programme for an interview.

As well as having a laugh about the hassle I had with HMRC’s phone system, we talked about the serious implications of the new rules for small businesses. One of the things we discussed was how many of them were struggling with the technological requirements that the new VAT rules imposed on them. While my experience of setting things up with HMRC had bordered on farcical, I had the skills and experience to implement the changes that many other small businesses didn’t.

I’m not an accountant, I’m a software engineer. I’ve built a career around software automation — I know how to make systems work together. But I’ve also run a small business. My old friend, Paul Basham, a chartered accountant, now also working with us at untied, told me the other day that he has always been impressed by how much I — a lowly software developer — know about tax and accounting.

More importantly I think, running a small business means I also know how scary tax can be, what it’s like dealing with HMRC and worrying about how to account for things properly and getting things in on time. I’ve also seen friends and loved ones worrying about their tax return, fearing they’re going to get in trouble if they get something wrong.

Speaking of friends and relatives, if you work in IT you’re the guy they call when their laptop won’t boot up or they need to buy a new monitor. And at tax return time you’re the one they come to when they mess up the spreadsheet their accountant gave them!

So, when Kevin called me early last year and asked if I wanted to help build a tax app for ordinary people, it all just made perfect sense. I had a bit of tax knowledge and I had the software engineering skills and experience to make it all work. But above all else I knew what doing your taxes is like. I felt the pain. I wanted to fix it. So, I jumped right in and started coding, even though it meant I might have to communicate with HMRC again!

Eighteen months later, I’m really proud of what we’ve achieved. We’ve been through two prestigious business accelerators — Accenture Fintech Innovation Lab and Barclays Techstars — had our technology recognised by HMRC and become regulated by the FCA.

untied is born

untied is a mobile app for anyone who has to do a personal tax return. It connects to your bank accounts, makes tax sense of transactions as they come in, offers insights and provides ways to automate income/expense tagging. untied provides a real-time tax calculation, showing you exactly what you will need to pay and providing a useful overview of how your business is doing. And when it’s tax return time you can submit directly from the app.

We have big plans and there’s lots to look forward to. To try out the app or find out more, go here.



Marcus Tettmar
Editor for

CTO/Co-founder https://untied.io —the personal tax app. Developer/Co-Founder https://nerdlegame.com. Founder https://mjtnet.com — RPA software for all.