How OpenBooks works, in plain English.
You don’t need to be an accountant to keep accountant-grade books. This guide explains how OpenBooks thinks, what it does on its own, and the small amount it needs from you — without any bookkeeping jargon on the surface.
AI proposes. The books post.
The AI reads each transaction and suggests where it belongs — but it never writes the final record by itself. A separate, careful accounting engine is the only thing that actually posts to your books, and it refuses to post anything that doesn’t balance. The AI is the smart assistant; the engine is the careful bookkeeper that signs off. That split is why an AI mistake can never quietly corrupt your numbers: at worst it suggests the wrong category, you fix it in one click, and the engine re-posts it correctly.
Your books always add up — and you never have to think about why.
Under the surface, OpenBooks keeps double-entry books— an accounting method where every transaction is recorded in two places at once (where the money came from and where it went) so the two sides must always match. It is the same method every serious accounting system uses, and it’s why your Profit & Loss, Balance Sheet, and Cash Flow always agree with each other instead of drifting apart.
You will never see the words “debit” or “credit” while running your business. You see income, expenses, and categories. The double-entry machinery runs entirely out of sight — unless you (or your accountant) deliberately open the optional accountant view to inspect it.
How money flows in — and where the Inbox fits.
Every transaction that arrives — from a connected bank, from Stripe, or from a file you import — runs through a quick set of checks, cheapest and most certain first:
- 1Is it a transfer?
Money moving between your own accounts isn't income or an expense — it's recognized as a transfer and left out of your profit.
- 2Does it match something you're expecting?
An invoice you sent, a bill you entered, a payroll payment, or an expected payout gets linked to it automatically.
- 3Does one of your rules claim it?
If you've told OpenBooks "anything from this vendor is software," it follows that.
- 4Has it seen this before?
OpenBooks remembers every correction you've made and applies what it learned.
- 5Otherwise, the AI categorizes it
with a confidence score and a short reason you can read.
When OpenBooks is confident, the item posts to your books on its own. When it isn’t, the item lands in your Inbox— the only part of OpenBooks that genuinely needs you. Most weeks that’s a handful of cards: confirm a category, correct one (which teaches it), match a receipt, or approve a transfer. Inbox empty means your books are done.
How much you let the AI do on its own.
You choose how confident the AI has to be before it posts something without asking. You can change this any time in Settings.
The AI never posts on its own. Everything it categorizes waits for your one-click confirm. Maximum control.
The AI posts when it's highly confident and sends only the genuinely uncertain items to your Inbox. The recommended setting for most owners.
The AI posts more freely and reserves your Inbox for the trickiest items. The most hands-off setting.
Whatever you choose, every posted item is labeled with how it got there (“Categorized by AI · 96%”), and nothing is ever permanent — any item can be corrected, and the books re-post cleanly.
What each screen does.
Your business at a glance: cash on hand, profit so far, who owes you and who you owe, where the money went, and the few Inbox items that need you. Every number clicks through to the transactions behind it.
The full list of money in and out. Search, filter, split one charge into parts, or change a category. Changing history never erases anything — the old entry is reversed and a corrected one is added, so your audit trail stays clean.
Money coming in: payments received, the invoices you've sent, and who still owes you, sorted by how overdue they are.
Where money goes, grouped by category and vendor, with the change from last month and the subscriptions you pay on repeat.
Money you owe. Add a bill by hand or drop in a receipt photo or PDF; mark it paid when the money leaves your account.
Your customers and vendors — created automatically as money moves — each with their full history and balance.
Pay your team in any currency. Open a run, set the amounts, approve it (which records the cost), and mark it paid. You get a printable statement. OpenBooks tracks pay; it does not file taxes or move the money for you.
Plain-English reports for any date range: a one-page Monthly Review, Profit & Loss, what you're owed and what you owe, cash flow, and the formal statements your accountant expects. Export any of them; the file matches the screen.
Ask your books a question in plain words — "How did last month compare?", "Who owes me money?" — and get an answer drawn from the same records the reports use. If you ask it to do something, it shows a card and waits for your OK first.
Your businesses, your keys and connections, the AI provider and how much freedom it has, your categories and rules, your team, and a full export of your data whenever you want it.
Running a portfolio of businesses.
If you run more than one company, OpenBooks gives you two ways to look at your money, and you can switch between them instantly.
Each company keeps its own complete, legally-separate books. If you move money from one of your businesses to another, OpenBooks shows it as a transfer between your businesses — never as income or an expense — so neither company’s profit is overstated.
The portfolio view rolls every business into one combined picture and cancels out the money you moved between them, so you see the true total — what you actually earned and spent across everything, with no double-counting.
Underneath, each company stays its own separate legal entity with its own books — which is exactly what your accountant and the tax authorities expect. The portfolio view is a lens on top of those separate books, not a merge.
Your keys, your data.
OpenBooks is bring-your-own-keys: you connect your own AI provider, your own bank link, and your own payments account. You are never billed by OpenBooks for any of it — your only costs are your own usage of those services (often just a few dollars a month).
Every key you connect is encrypted before it is stored and is never shown back to you — the app only ever displays a masked hint like the last four characters so you can tell which key is which. For the full technical posture, see the security page.
Owner FAQ.
Is my financial data private?
Yes. OpenBooks runs on your own deployment with your own database. The keys you connect — bank, payments, AI — are encrypted before they are stored and are never shown back to you or sent to anyone else. There are no ads and no tracking funnel.
What happens if the project stops being maintained?
Your books are a file you own. You can export everything (a spreadsheet, a data file, or an accountant-grade ledger export) at any time. Because OpenBooks is open-source under the permissive MIT license, anyone — including you — is free to keep running it. There is no company that can switch it off and take your data with it.
Will my accountant accept these books?
That's the whole point of keeping real double-entry books underneath the plain-English surface. You can hand your accountant the General Ledger, Trial Balance, and Journal exports they already know how to read.
Do I still need an accountant?
OpenBooks keeps your day-to-day books correct and ready. Many owners still want an accountant for taxes and year-end advice — OpenBooks gives that accountant clean, exportable books to work from instead of a shoebox of receipts.
What if the AI gets a category wrong?
Correct it once, and OpenBooks remembers — the next similar charge follows your correction, and after a few identical fixes it offers to make a rule for you. Nothing is ever stuck: every change can be undone, because corrections are added as new entries rather than edits.
Can I use OpenBooks without connecting a bank?
Yes. If you don't want to connect a bank through Plaid, you can import a CSV or OFX file from your bank instead — it runs through the exact same pipeline.
See it with real data — no login.
The fastest way to understand OpenBooks is to open the live demo: a fully seeded set of books you can click through end-to-end. Nothing you do there is saved, and it resets daily.