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Case study · Buzz OS

An operating system
for an accountancy firm

Twenty-plus modules, 487 live clients and HMRC-grade tax filing — built from scratch to replace every piece of third-party practice software.

The brief

The off-the-shelf options were project-management tools dressed up as practice management. None handled a real sales pipeline, staff capacity and deep HMRC and Companies House integration in one place.

So we built it. It now runs the whole firm — first prospect call through to filing a tax return. The software it replaced is switched off.

What we built
  • Two-pipeline CRM — new prospects and existing-client opportunities, with automatic price-review detection against turnover
  • Jobs, tasks and capacity — recurring compliance jobs generated from Companies House deadlines, rated against a real hours baseline
  • Onboarding end to end — proposal builder with discounting, engagement letter, e-signature, HMRC agent authorisation, AML check and direct-debit mandate
  • Full HMRC Making Tax Digital agent software — digital records, cumulative quarterly submissions, year-end and Final Declaration
  • Six AI agents — chasing information requests, nudging stalled onboarding, triaging the inbox, pre-reviewing jobs, orchestrating each new client
  • A grounded assistant answering staff questions from a curated tax knowledge base rather than from memory
  • Client portal with no login — a private link per client to approve proposals, answer requests and upload files
  • The rest of the business too — time and WIP with job profitability, HR and holidays, a team hub, booking pages, an installable mobile app
487live clients running on it
20+modules, CRM to tax filing
6AI agents working daily
48database migrations and counting
Where it got to

Software that files tax returns.

Buzz OS cleared HMRC's full production checklist for Making Tax Digital agent software, with every submission type verified end to end against HMRC's own sandbox — records, quarterly updates, year-end and Final Declaration. That's the highest compliance bar in UK accounting software, met by a platform we built ourselves.

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