Context
Many organisations price in a spreadsheet, lay out in a word processor, then re-key everything into an invoicing tool. Every move from one medium to another is an opportunity for error, and invoicing errors cost both cash flow and credibility.
The problem
The problem is not the arithmetic, it is the continuity between steps.
- Quote and invoice live in two tools, with two possible versions of the truth
- A change of scope during negotiation means redoing everything
- VAT rates and mandatory statements are copied by hand
- Invoice numbering has to be continuous and gapless, which a spreadsheet cannot guarantee
The solution
One tool where pricing produces the quote, and the accepted quote becomes the invoice with no re-keying.
- Quote settings on one side, document preview on the other, updated live
- Editable line items, with quantities, unit prices and discounts
- Automatic calculation of subtotal, VAT by rate and gross total
- Conversion of the accepted quote into an invoice, keeping the link between the two
- Continuous invoice numbering, guaranteed by the application
- PDF generation, faithful to the preview on screen
My role
Design of the document model and the calculation rules, development of the API and the editing interface, document generation and numbering management.
Constraints
- Accuracy of calculations, including rounding and multiple VAT rates
- Continuous legal numbering, without gaps or duplicates, even after an incident
- Mandatory statements present on every issued document
- The generated PDF has to match exactly what was displayed
- Issued documents to retain and retrieve, with no retroactive modification
Outcome
A continuous chain from pricing to invoice, where the total shown during negotiation is the total that gets invoiced.
- No re-keying between quote and invoice, and therefore no gap between them
- Numbering is held by the application, not by a human convention
- The PDF is faithful to the preview, which removes unpleasant surprises on sending
Outcomes are described by the capability delivered. No commercial performance metric is claimed here: usage figures belong to the client, and I do not publish numbers I cannot substantiate.