About Daybook

What it is

Daybook is a shared book of a small business’s daily takings, expenses and profit. Several people belong to one organisation and keep one book between them. Whoever closes the register files the closing; whoever answers for the money reads the month.

It is a web page. There is nothing to install on a machine behind the counter and nothing to keep updated. It can be added to a phone’s home screen, after which it opens like an app.

Where it came from

It began as one shop’s cash book: a single-file application written for one business, in Greek, with that business’s shifts, its banks and its own way of counting a drawer written straight into it. It worked, and then other people wanted it.

Generalising it meant taking out everything that was true only of that one shop and leaving the part that turned out to be the same everywhere. A day has takings. A month has costs. Some of what is left is profit, and some of it only looks like profit. That is the whole of it.

What survived from the original is the shape of the screens and the arithmetic. What went was the assumption that there is one business, one language, one currency and two owners who both already know everything.

How it treats money

One chain, from what came through the register to what is actually left:

Two of those steps are the ones a hand-kept book gets wrong, so they are worth stating plainly.

• A withdrawal is not an expense. Money an owner takes for themselves is profit being distributed, not a cost of running the business. Counting it as a cost makes a good month look like a bad one, and it is the commonest mistake in a notebook. Withdrawals are shown apart from expenses everywhere in the app, and they never appear in the chain above.
• A cheque is not a purchase. The supplier’s invoice is the cost, and it was already counted in the month it belongs to. The cheque that pays it moves money out of an account; it does not add a second cost. Marking an obligation paid changes what you owe, never what you spent.
• A claim’s deduction rate is derived, not assumed. Where money is billed to a third party and paid later minus deductions, the rate is measured from the organisation’s own settled periods — what was submitted against what actually arrived. Nothing is hardcoded, because no two payers and no two years are the same. Before anything has settled there is no estimate, and the app says so rather than inventing one.

Who can see what

There are four roles — owner, admin, cashier and viewer — and then a permission checkbox per person, so a role is a starting point rather than a cage. Change one box and the role is shown as Custom.

The unusual part is where those rules live. Most applications decide what you may see while building the page they send you, which means the rule is enforced by not drawing a button. Daybook’s rules are written into the database as row-level security policies: every single query asks the database whether this person may have this row, and the database answers.

So a cashier who asks for last month’s profit is refused by PostgreSQL, not by a missing menu item. Hiding a control here is a courtesy — it keeps a screen from offering something that would only fail. It is not the security. Nothing changes if someone opens the browser’s developer tools.

What it is not

• Not accounting software. No double-entry, no statutory accounts, nothing filed with anyone on your behalf.
• Not connected to anything. No bank, no card terminal, no tax authority, no accounting package. Every figure in the book is there because a person typed it or imported it.
• Not a till. It does not ring up sales or print receipts. It records what the till said at the end of a shift.
• Not an offline app. It needs a connection. Without one it shows a page saying so; it does not hold entries back to send later.

When your accountant needs the figures, you export them and send them. Nothing leaves on its own.

Where the book lives

In one PostgreSQL database in Frankfurt, Germany. Business data does not leave it.

There is no analytics, no tracking, no advertising and no third-party script of any kind — while you use it, the browser talks to that database and to nothing else. An owner can export the whole book as a file, and can delete all of it. The privacy notice sets out the detail.