When a customer does not pay an invoice, the accounting tool eventually speaks up. An open receivable becomes visible, there may be reminders, or at least a list of overdue payments. The other case is harder: no invoice was issued at all. Then there is no receivable, no due date, and no signal in the accounting system. No tool can chase an invoice that was never created.
This can happen with ongoing contracts. Work is delivered, time is documented, the month passes, and among other tasks the invoice is not prepared. The mistake often appears late, when someone looks back and notices that no revenue was documented for a period.
Invoices stay in the accounting tool
Invoices themselves continue to be created where accounting happens, such as DATEV, Lexware, or another specialised tool. The toolkit does not replace those systems or maintain invoice data twice. It needs neither invoice line items nor payment status.
Once an invoice exists, only its invoice number is recorded for the relevant contract and month. That records one thing: an invoice was created for this period. Nothing more needs to be stored here.
Making the gap visible in the contract overview
The contract overview makes it clear when an ongoing contract has not been assigned an invoice for a long time. This is not a judgement about whether a customer has paid. It answers the earlier question: did we issue an invoice for the work delivered at all?
That is the difference from an overdue receivable. Accounting recognises an overdue invoice. A missing invoice must first become visible in the work and contract context.
A short entry instead of duplicated data
The flow remains deliberately lean: create the invoice in the accounting tool, record the invoice number on the contract for the month, done. Accounting remains the source for the invoice; the contract context shows whether billing for an ongoing collaboration was forgotten.
This does not create a second accounting system. It creates a reminder in the right place, where running contracts and the months in which work and billing belong together are visible.
Liquidity starts before a reminder
This small visibility can matter for liquidity. Not every missing payment is late payment. Sometimes the first step is simply missing. Recognising missing invoices early makes it possible to issue them before a forgotten bill becomes an unnecessary hole in cash flow.