Professional Invoices, Instantly

Build an invoice workspace for a freelance designer. Maintain clients, line items, tax settings, payment status and sequential invoice numbers, with printable invoices and draft editing.

Include these capabilities:
- Customizable invoice templates
- Client and contact management
- Automatic tax calculations
- PDF generation and email sending
- Payment status tracking and reminders

Build the complete working project with its routes, data model and interactions. For saved or private data, implement persistence, authentication and server-side permissions. Keep API credentials on the server. For external services, document the required setup and use test mode until real accounts are connected. Do not present a simulated integration as a completed live connection.

Make the interface responsive, with accessible labels, keyboard navigation and visible focus. Include loading, empty, validation and error states. Use clearly labelled sample data, never invented customer testimonials or results. Choose a visual direction suited to this project and keep typography, spacing and controls consistent. Explain how to run, test, export and deploy the source.

Verify this end-to-end flow:
Create a draft, add a discount and issue a PDF. Verify line totals, rounding and numbering; prevent an issued invoice from being silently overwritten.