Why DUE never links your bank — and how it works instead

Almost every budgeting app opens the same way: connect your bank. It feels like the modern default. I built DUE to do the opposite — there is no bank login anywhere in the product, and there never will be. This isn't a feature we haven't got to yet; it's the foundation. Here's why, and how the app actually works without it.

The two things that break every money app

Read the reviews of any bank-connected finance app and the same two problems dominate. First: the sync breaks. Banks change their systems, connections drop, re-authentication loops, and suddenly your "automatic" budget is stale and wrong. Second: the fear. Handing a third party a live line into your bank is the single most sensitive thing a finance app asks of you, and every breach headline makes people more nervous.

Both problems have the same root cause — the bank connection itself. So DUE removes it. There is no sync to break, and there is nothing to leak, because the connection that would leak was never made.

How DUE knows your bills without a bank

Two ways, both under your control. You can add a bill, subscription or income in a few seconds — DUE understands plain phrases like "Netflix 12.99 monthly from Friday". Or you can photograph or upload a document — a bill, an invoice, a screenshot — and DUE reads it and fills in the amount, date, vendor and recurrence for you to confirm before anything is saved.

• You confirm every extracted field. The app proposes; you decide.
• It handles one bill or a statement with several separate charges.
• Nothing is auto-imported behind your back — there's no transaction feed to import from.

The rule that matters most: AI reads, code decides

This is the part I'm most careful about. The AI in DUE only ever does language work — turning a document or a sentence into structured fields. It never does the maths, and it never gives financial advice. Every number that matters — what's safe to spend, what's due before payday, your projected balance — is computed by plain, deterministic code, the same way a calculator is deterministic. Ask the same question twice and you get the same answer, because a model isn't inventing it.

That's a deliberate line. An LLM confidently making up a figure about your money is exactly the failure I refuse to ship. So the model is kept on the language side of the fence, and the arithmetic lives in code that's tested and predictable.

Under the hood, briefly

A few engineering choices follow directly from taking your money seriously:

• Money is stored as whole units of the smallest denomination (cents), never as decimals — so there's no floating-point rounding drift in your totals.
• Every record — bills, income, documents, settings — is isolated to your own account at the database level, so one person's data can't be read by another.
• Documents you scan are read once to pull out the details, then not stored — only the item you save is kept — and nothing you scan is used to train AI models.
• It's euro-native and multi-currency, using published exchange-rate data — useful if you hold Revolut or Wise balances that bank-linked apps handle badly.
• It runs as a web app and as real downloadable desktop apps for Mac and Windows — no app store required.

The honest tradeoff

There is a cost to this design, and I'd rather say it plainly: you don't get an automatic transaction feed. You add or scan the things you want to track. For the people DUE is for — privacy-minded, often in the EU, tired of broken sync — that's a fair and even welcome trade. If what you want is every coffee auto-categorised from a live bank feed, DUE isn't your tool, and that's fine.

What you get in return is a money app that can't break the way the others do, can't leak what it never holds, and answers the one question that actually changes a spending decision: after everything I already owe, how much is really mine until payday?