What is invoicing and PDF generation?

Invoicing is the process of generating a formal document that records a transaction and requests payment — or confirms that payment has been received. In an app context, this means generating a PDF (or HTML-rendered equivalent) that includes all the information required by the ATO for a valid tax invoice, delivering it to the recipient, and providing an online portal where they can view and download past invoices.

This is distinct from the receipts that payment processors like Stripe generate automatically. Stripe receipts confirm a payment occurred; a tax invoice is a legal document that supports the recipient's GST input tax credit claims. If your customers are businesses, they need proper tax invoices, not just payment receipts.

Generating PDFs from application data sounds simple but involves layout complexity, data consistency, sequential numbering, and audit requirements that accumulate quickly.

When does your app need it?

• Your customers are businesses that need ATO-compliant tax invoices for GST purposes
• You're building a billing or quoting workflow where invoices are created before payment (not after)
• You need to send invoices via email as PDFs and provide an online portal for customers to access their history
• You want to sync invoice data with accounting software (Xero or MYOB) used by your customers
• Your invoices need to include project-specific line items, purchase order numbers, or custom fields that Stripe's built-in receipts don't support
• You're replacing a manual process (Word documents, Excel) with automated invoice generation

How much does it cost?

Adding invoicing and PDF generation typically adds 8–16 hours of development — roughly $1,000–$4,000 AUD.

At the lower end: generating PDFs using a template library (React-PDF or PDFKit), a basic invoice number sequence, email delivery, and a simple invoice list page. If your invoices have a straightforward layout and you don't need accounting system integration, this is achievable at the lower end.

At the higher end: a full invoice portal (list, view, download, mark as paid), Xero or MYOB sync via API, credit notes and adjustments, support for multiple invoice templates, custom line item types, recurring invoice generation, and overdue reminders. Xero integration alone — OAuth connection, invoice push, payment reconciliation — can be 4–6 hours.

How it's typically built

PDF generation in Node.js is handled by one of three approaches:

• React-PDF (@react-pdf/renderer): write the invoice as a React component with PDF-specific layout primitives. Good for developers comfortable with React; produces consistent output.
• PDFKit: a lower-level Node.js library that draws to a PDF canvas programmatically. More control, more verbose.
• Headless Chrome / Puppeteer: render the invoice as HTML/CSS in a headless browser and print to PDF. Best for pixel-perfect designs that match your web UI, but adds server resource overhead.

ATO-compliant tax invoices must include: supplier name and ABN, date of issue, a unique invoice number, a description of the goods or services, the GST amount (or a statement that the total includes GST), and the total amount payable. For invoices over $1,000, the recipient's name or ABN is also required.

Invoice number sequences need to be collision-proof — a database sequence or a locked counter ensures no two invoices share a number, even under concurrent requests.

Xero integration uses Xero's OAuth 2.0 API. Invoices are pushed to Xero as draft or approved invoices, and payment records can be synced back. Each customer needs to connect their Xero organisation — this is a per-customer OAuth flow that needs UI and token storage.

Questions to ask your developer

• Which PDF generation approach are you using? React-PDF and Puppeteer both work well — the choice affects server resource requirements and how easily the layout can be changed.
• Does the invoice include all ATO-required fields? ABN, GST amount, unique invoice number, and issue date are mandatory. Ask your developer to confirm against ATO tax invoice requirements.
• How is invoice numbering handled? Sequential numbers must be unique and gap-free. Ask how concurrent invoice creation is handled.
• Are credit notes supported? If customers need to dispute or adjust an invoice, a credit note is the correct accounting instrument — not a deletion.
• Is Xero or MYOB integration in scope? If your customers use accounting software, syncing invoices saves them manual data entry and is a meaningful feature.

---

See also: One-off payments · Subscription billing · GST calculations · App cost calculator