Accounting practice software
Fynvro OS
Every UK statutory deadline generated automatically, plus daily Xero checks that flag what is wrong before it falls due.
Free, then from £29/month
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UK software company · Three products
Software that tells you what to do next, not just what happened.
Fynvro builds Fynvro OS for accounting practices, SellerControl for UK eBay sellers, and Fynvro Web — practical products for the work that slows a business down.
DetectExplainAct
What we build
Three products designed to help businesses work better.
Each one solves a real, specific problem — built to detect what matters, explain what it means, and help you act.
eBay seller software
SellerControl
Captures what you actually paid your supplier, matches it to the sale, and shows real profit per order.
Free, then from £12/month
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Websites & AI
Fynvro Web
Websites with AI assistants built in. Fixed packages, live in 14 days.
From £399
Learn more →LiveAll three products running in production
Built withA UK practice supporting 1,500+ clients
ProvenBuilt and run in a real eBay shop
RegisteredFynvro Ltd 17287290 · England & Wales · ICO registered
The problem
Most business software tells you what happened. Almost none tells you what to do about it.
A practice-management tool lists your jobs. A marketplace shows you your sales. A website collects a form. Each one hands you data and stops — leaving you to work out what it means and what needs doing today. That gap is where the work piles up, and it is the gap every Fynvro product is built to close.
How we build
Every product runs in a real business before it ships.
Every Fynvro product runs in a real business before it ships. Features are tested against real work, not a roadmap. SellerControl runs a real eBay shop. Fynvro OS is used by a UK accounting practice supporting 1,500+ clients. Nothing ships because it demos well.
Who it is for
Built for the businesses that do the work themselves.
UK accounting firms
Practices that need to know what is missing and what is due, across every client, without building a spreadsheet to find out.
eBay sellers
Sellers sourcing stock from suppliers who want to know their real profit per order, not just what the marketplace paid out.
Local UK businesses
Businesses that need a site that actually captures leads, with an assistant that answers when they cannot.
Latest writing
Notes from building it.
eBay
eBay tells you what you sold, not what you made
Why marketplace data alone cannot show a seller their real profit.
Accounting
What practice management should actually mean for UK firms
Most tools track jobs. The useful question is what needs attention today.
Philosophy
Detect, explain, act: the loop behind every product
The three-step idea that shapes how we build every Fynvro tool.
Ready to work with clarity?
Let's build systems that help your business work better.
Get in touch to learn how Fynvro can help.
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