Invoice Studio

A tiny, private invoicing app that runs entirely on your computer. No accounts, no database, no cloud — one HTML page, one optional local server, and your data in a plain JSON file you own.

Built for freelancers and small studios who want to make clean invoices and keep an eye on their numbers without signing up for anything.

Features

• Invoices — line items, four currencies ($ £ € ₺), tax/VAT, live A4 preview that always fits one page, PDF export (print → "Save as PDF")
• Clients & services — save the people you bill and the things you bill for; add them to an invoice in one click; import clients from CSV
• Expenses — one-off, monthly, or yearly business costs by category
• Savings — track cash savings and reserves alongside the business
• Dashboard — revenue, expenses, projected net profit and tax for your fiscal year, a monthly revenue chart, and a hand-built SVG Sankey diagram showing where the money flows
• Yours to style — the invoice design lives in one CSS file (public/invoice.css); the accent colour, logo, and business details come from Settings

Run it

Easiest: open public/index.html in your browser. Done. Data is saved in the browser (localStorage).

Recommended: run the tiny local server so your data is written to a real file (data.json) you can back up or sync:

node serve.js

then open http://localhost:4242. No dependencies — Node.js is all you need.

Your data

• Browser mode: stored in localStorage on that device.
• Server mode: stored in data.json next to serve.js (gitignored — never commit it).
• The Back up my data button downloads everything as a single JSON file; restore from Settings.

Customising the invoice

• Colours, spacing, typography: edit public/invoice.css (every class is prefixed inv-).
• Markup/structure: edit renderInvoiceTicket() in public/invoice-template.js.
• Keep the .inv-page → .inv-ticket-fit → .inv-ticket wrapper structure — that's what guarantees the invoice always scales to a single A4 page, on screen and in the PDF.

License

MIT — see LICENSE.