I Built a (Mostly) Free AI Accountant Because the Shoebox Has to Die

It's the last week of January. You've been meaning to sort your books for a year. Instead, you've got a shoebox.

Inside the shoebox: fuel receipts, a creased invoice from a plumber who did a one-off repair at the office, two taxi receipts from a trip to Birmingham you can't quite remember the purpose of, a stack of Amazon packing slips that double as receipts if you squint, and the wristband from a conference you attended in May. Somewhere in there is a business rates demand you've been ignoring. Your accountant needs everything by Friday. Your spouse has already moved the shoebox twice.

I've watched small-business owners open that shoebox and physically wince. Not because the numbers inside are bad — usually they're fine — but because the cost of turning the shoebox into accounts is a weekend they'll never get back, plus a bill from someone with letters after their name who is charging them for the privilege of sorting through their own life.

Managing accounts is yet another tax on entrepreneurialism, but it is one that we can do something about.

The problem isn't accounting. It's everything around accounting.

The actual accounting bit — debits on the left, credits on the right, here's what you owe HMRC — hasn't fundamentally changed since the Medici. What has changed, relentlessly and for the worse, is the amount of admin sitting between a small-business owner and a clean set of books.

20 years ago you had paper. 10 years ago you had Xero plus a bank feed plus Dext plus a VAT bridging tool plus a spreadsheet your accountant wanted populated in a very specific way. Today you have all of those and Stripe, and a payment link from a marketplace, and a sales channel that pays out net of fees, and an AI-generated invoice from a supplier who doesn't use the same format twice in a row.

Every one of those adds a tiny bit of friction. Individually, none of them is worth complaining about. Collectively, they're the reason the shoebox survives. The shoebox is what happens when the cost of doing it properly quietly exceeds the cost of putting it off.

This is a good moment to try something new

I've been building in and around the finance stack for a while. For most of that time, the honest answer to "can an AI do my books?" was no, not really, and anyone selling you that was selling you a glossy chatbot glued to a brittle rules engine.

Somewhere in the last eighteen months that answer has quietly changed. The model that matters here is the one I use every day: Claude, running agentic workflows through Claude Co-Work. For the first time, a general-purpose model is reliably good enough at structured tasks — reading a PDF invoice, reconciling it against a bank line, choosing the right ledger code, flagging the edge cases — that the bit worth automating is actually automatable.

Not the arithmetic. Nobody's automating the arithmetic; a calculator did that. What's automatable now is the judgement around the arithmetic. Which account does this belong in. Is this a reimbursable expense or a supplier payment. Should this be accrued. Is this VAT-reclaimable — I have the customer invoice, but where are the associated cost invoices?

Those are the questions the shoebox is full of. That is what I decided to build against.

The thing I keep coming back to: your accountant is valuable because they remember

The single most useful frame I've landed on while building Luca is a human one. A good accountant who has known your business for three years is worth far more than one who started last week. This is obvious once you say it out loud, but it's an under-appreciated fact of how small-business accounting actually works.

Your three-year accountant knows that you and your co-founder split the one time you both tried to take a dividend on the same day, and the messy journal that fixed it. They know the lease on the storage unit is in your personal name but the rent runs through the business because that's how the landlord wanted it. They know that the quarterly payment to the guy in Portugal is not a recurring supplier, it's a royalty on something you bought the rights to in 2021. They know which of your expense categories is where you quietly bury the stuff you're not sure about, so they can ask a real question about it in February instead of categorising it wrong in April.

Software, traditionally, has been the opposite of this. It's been a new starter, every day, forever. Every quarter you re-teach it which supplier is which. Every VAT return it flags the same transactions it flagged last time. Every migration you lose whatever institutional memory you'd managed to encode into account codes and custom tags, because the new system doesn't import them cleanly.

The thing that's different about an AI accountant — done right — is that it can actually hold context the way a human accountant does. Not pattern-match rules. Actually remember: this supplier, this coding treatment, this edge case, this conversation we had three months ago when we decided how to handle it.

That memory, compounding over time, is most of what you're paying for when you pay a good accountant. It shouldn't be the thing that's missing from software.

And here's where Luca has an edge your human accountant can't match. Luca will learn your business — every supplier, every quirk, every coding decision — and then, unlike the brilliant junior at your accountancy firm who gets poached in eighteen months, Luca will never leave. He doesn't retire. He doesn't go on holiday at year-end. He doesn't get promoted away from your account.

He costs a fraction of what a human bookkeeper costs, and he's online at three in the morning on a Sunday before your VAT deadline. He works bank holidays and over Christmas and 24 hours a day — which is exactly when you need him and exactly when no accountant is picking up the phone.

The compounding memory of a long-term accountant, with none of the churn and none of the hourly rate. Luca is my attempt to build software that gets better at your books the longer it looks at them, the same way a human accountant does — because it's the first era of software where that's actually possible.

What Luca actually does

Let me be concrete, because "AI accountant" is a category label that's been abused by roughly every fintech deck on the internet. Luca is a real general ledger with real double-entry, and the parts that are genuinely automated are these:

• Document ingestion. You forward or drop any finance document — supplier invoice, customer invoice, receipt, payment confirmation, bank statement, credit note — and Luca reads it, extracts the relevant fields, proposes the posting, and either posts it straight through or queues it for your review depending on the confidence score. This is the shoebox-killer. You don't sort the shoebox. You empty it into the inbox, or just use your phone to scan it into the inbox.
• Bank reconciliation. Connect your bank feed and Luca matches transactions against posted documents, flags what it can't match, and proposes what to do with the orphans — is this a new supplier, is this an owner's draw, is this a payment against an invoice we haven't seen yet. The bits that need a human stay with the human. The bits that are obvious get done.
• VAT returns and period closes. Full Making Tax Digital-compatible output, with the computation shown, not hidden. Period closes with proper lock, full audit trail, Merkle-chained journal for immutable history. The rigour is there; the boredom is not.
• Reports that make sense. P&L, balance sheet, trial balance, aged debtors, aged creditors — all generated live from the ledger, all with the underlying transactions one click away. If a number looks wrong you can immediately see the thing that's making it wrong. That's it — no magic, just a ledger that doesn't hide from you.

And if you want to know more about a specific report, just ask Luca — he is surprisingly chatty and knowledgeable.

The great thing about Luca is that he covers everything from posting individual invoices like an accounts clerk, to reconciling the bank account, to producing the weekly or monthly reports like a financial controller might do — and he can even do some of the jobs you'd more commonly associate with a full CFO: advising you on how to structure your financial disclosure, where to look to get extra profit out of your business, or warning you about potential regulatory issues.

What Luca is not

I want to be unusually direct about this because I think it's where most finance tools lose credibility. Luca is in beta. That is a feature right now, not a bug — it means I'm responsive, I'm actively shaping it around real users, and it's free while that's true. It also means there are specific things it is not yet the right tool for:

• It's not the right tool if you need a statutory audit.
• It's not ready for multi-entity group consolidation.
• It's not built for charity-specific reporting (SORP), and I'd be cautious about using it as the primary system for anything where regulatory filings depend on features I haven't built yet.

If you're a straightforward UK limited company, sole trader, or partnership with a normal set of books, you are squarely in scope. If you're outside that, talk to me before you commit to it — I'd rather lose the conversation than lose your trust.

Why open, and why free for now

Two decisions that aren't obvious from the outside.

Open: the code is on GitHub. Anyone who wants to host their own instance can. Anyone who wants to audit how a number is being calculated can read the function that calculates it. I think the era of opaque finance software — where the vendor hides the logic and you have to trust the output — is ending, and good riddance. If Luca is going to be your ledger, you should be able to see what it does to your numbers.

Free for now: charging money for a beta would mean I have to defend the product in ways that slow me down. I'd rather have users who are in because they want to kick the tyres, help me find the edge cases, and tell me what's broken. Pricing will come later, and when it does it will be honest — a small-business accounting product sitting squarely in the bracket of "much cheaper than a bookkeeper, much more capable than a spreadsheet."

If you want it built around your business

Most small businesses can drop Luca in and it'll work out of the box. But some of you will have a chart of accounts that does things its own way, a trade-specific workflow, an integration you need that isn't in the standard setup, or simply the appetite to roll your sleeves up and help shape the product.

For a one-off £500, I'll sit down with you and customise Luca to your business — your chart of accounts, your reporting, your particular edge cases, any bespoke logic you need. You'll also get direct input into the roadmap, because the businesses who get involved early get to steer where this goes next.

After that £500, you're on the same free beta as everyone else — just with a Luca that's configured the way your business actually runs, and a direct line to the person building it.

This is not upsell theatre. It's genuinely the fastest way to get Luca doing something useful for a non-standard business, and the best way to make sure the product ends up built for real businesses rather than hypothetical ones.

If you've read this far

Three things you can do:

1. If you run a small business and the shoebox is making you ill — the site is luca-accountant.com. There's a DIY installation guide if you want to self-host, and a hosted plan you can sign up for if you don't. It takes about an hour to go from nothing to your first posted invoice.
2. If you're an accountant, I'd particularly like to talk to you. I'm not trying to replace you; I'm trying to kill the bit of your job that makes you want to replace yourself. The practices I've spoken to so far have been more enthusiastic about this than I expected, because the shoebox is taxing them too.
3. And if you just have thoughts, push back, war stories, or a category of business I haven't thought about — get in touch. The fastest way to make this good is for people who actually do the work to tell me what's wrong with it. That's worth more to me right now than any marketing channel.

The shoebox has had a good run. It's time.