I did not set out to build a finance tool. I am a builder by background, twenty-five years writing software for other people’s businesses, and somewhere along the way I started running a few of my own. Like every founder I learned, in the slowest possible way, that the actual work of running a business is not the product. It is invoicing, tracking time, chasing payments, talking to your accountant, and trying to remember which spreadsheet has the latest VAT export. The product is the easy part. The plumbing eats the day.
I tried the tools you have probably already tried. Harvest for time and the basic invoicing, Stripe for subscriptions, a separate bookkeeping package my accountant insisted on, Notion for project tracking, and a handful of spreadsheets to bridge the gaps. Each tool was fine in isolation. Together they were a part-time job nobody had hired me for, on top of the actual work.
The thing that pushed me to start building was not a single moment, it was a pattern. Every quarter I spent a Sunday afternoon reconciling four systems for a single BTW-aangifte. Every year I found a new edge case my accountant needed in a format none of my tools produced. Every API integration I wanted to build hit a write-limit somewhere and turned a one-line automation into a nightly script. Every time I tried to ask “what was my actual margin on project X” the answer required exporting CSVs from three places and stapling them together in Excel. After enough of those Sundays I started prototyping the thing I wished existed.
What I wanted was simple to describe and hard to find. Time tracking that turned directly into invoice lines without copy-paste. Invoices with strict EU-compliant numbering, no gaps, no edits after sending, ICP and per-code VAT breakdowns produced automatically. A real double-entry ledger underneath, so reports were derived from data rather than assembled by hand. An API that did everything the UI did, signed webhooks on every state change, so my own automations could plug in without scraping. All of it on the same auth, the same data model, the same audit trail. Nothing on the market did all of that, plenty did parts of it, so I started writing the missing piece for myself.
The prototype became Rozuro. The principle I kept coming back to is one source of truth, accessed identically from the UI and the API. Every button you can click is also an endpoint you can POST to. The validation that prevents a bad invoice in a form runs verbatim against a JSON payload. The ledger writes are the same writes either way. Whether you live in the web app or run everything from your own code, you are touching the same data, and your accountant can verify the audit trail end to end.
That principle drove the design decisions that look strange in screenshots but pay off in practice. Invoices become immutable on send, and credit notes are how you correct them, like real bookkeeping has always worked. Numbering is enforced server-side with no draft-deletion gaps. VAT codes live on the individual lines so ICP exports fall out for free. Webhooks fire on every state change with signed payloads, so a Slack alert, a Stripe reconciliation, or a custom CRM integration is twenty lines of code instead of a Zapier subscription.
Rozuro is for people in roughly my position. Small-to-medium teams that need real finance plumbing rather than a prettier invoice template. EU-focused, because the compliance gap is sharpest there and that is the gap I spent ten years walking around. API-friendly, because most workflows worth automating are workflows nobody else has thought of yet. If you have ever rebuilt your own chart of accounts in a spreadsheet, you are our person.
The roadmap, candid version. A native iOS app, expense OCR (a third of early-user feedback asked for it), UBL/Peppol e-invoicing for the EU mandate cycle, and a broader integrations catalog so Stripe, Mollie, Xero, Exact, and the usual suspects work without you having to touch the API yourself.
If any of that resonates, the easiest thing is to start free at /register. There is no credit card. Or get in touch. I read everything in this phase, and the product gets sharper the more “actually what would help me is” emails I get.
Love, Marten.