About a month ago I started building QuarterPerfect — a bookkeeping tool aimed at UK sole traders and landlords, specifically designed around the MTD ITSA changes coming into effect this year (first quarterly deadline: 7 August).A bit of background on me firstly.I m not a senior developer. My previous project was a small roster app that converted an XLSX shift rota into a calendar with annual leave support — mostly built for me and a few colleagues at work. Nothing with real users, nothing with payments or compliance requirements. QuarterPerfect is a significant step up from that.QuarterPerfect offers users bank statement import (CSV and PDF), transaction categorization with receipt matching, merchant rules for auto-categorizing recurring transactions, and a read-only accountant share link so clients can hand off clean records without chasing. It s web-first with a mobile app in testing.The technical side was challenging but learnable. The harder thing was building in a domain I have no real background in. The HMRC/MTD space has a lot of nuance, treatment of different income types, what quarterly updates actually mean vs the annual return, what accountants need vs what HMRC needs. Getting that wrong isn t a UX problem, it s a liability problem.The second hard thing was learning to work effectively with AI assistance. I used Claude and Perplexity heavily throughout. Early on I d accept output too uncritically and build on shaky foundations. The shift that helped most was treating it less like a code generator and more like a pair programmer, the decisions still have to be mine, and I have to understand what I m shipping well enough to defend it. Honestly though, one really good work flow was to give Perplexity my ideas and have it generate detailed prompts for Claude, I would then post results back to Perplexity. A LOT of copy and pasting but results were spot on. I also had them both agree on a project management structure, which REALLY helped keep things tidy.It s still in testing, with no public users yet. The product works end-to-end but I m not comfortable pushing it to strangers until I m more confident in the compliance side. Also I want the app to be native to iOS and Google Play store, the latter requires me to have a minimum of 12 testers using the app in some capacity for 14 days, I haven t reached the minimum amount yet, even after asking for help from friends on social media, quite deflating to be honest!Has anyone else built in a regulated or compliance-heavy space without vast expertise? How did you handle the gap between this works and this is correct enough to trust with someone s tax records for example.Has anyone else found the AI-assisted development workflow genuinely helped them create a working/useful website/app, what has been your experience?I m not looking to recruit users from this post, the product requires signup to evaluate properly anyway. More curious whether anyone s been in a similar position and what they did to get it over the line.Thanks,James