Invoice

Line items with quantities and prices, a discount, a tax rate, your own details and your client’s. The total adds up as you type, and the same arithmetic runs again on the server when you save, so what you saw is what is stored.

Send your client a link. They need no account, they see the invoice laid out, and they can download it as a PDF. The PDF is drawn rather than printed from the page, so it looks the same whoever opens it and whatever browser they use.

Keep as many clients as you like. The thing that pushes people off invoicing tools is a plan that stops at five clients and then costs three times as much; there is no such step here.

Money is handled the way money should be: whole minor units, never a decimal fraction, with the currency’s own scale stored alongside each invoice so an old invoice still reads correctly if a currency changes later. An invoice that does not add up cannot be saved at all, because the database checks the lines against the totals when the change is committed.

What this does not do yet, and says so rather than implying otherwise: it does not email the invoice for you, it does not take payment, and it does not chase an overdue one. It makes the invoice, shares it, and tracks whether it has been paid.