InvoicePilot — B2B Invoicing API

InvoicePilot's backend exposes a versioned REST API consumed by both a web dashboard and companion mobile apps. It supports recurring invoice scheduling, multi-currency line items with live exchange rate lookups, and branded PDF generation queued to avoid blocking the request cycle.

I designed the API contract from scratch alongside the mobile team, including pagination, filtering, and webhook notifications for invoice status changes (sent, viewed, paid, overdue).

PDF generation for large invoices with many line items was initially synchronous and occasionally timed out under load. Moved generation to a queued job with a polling endpoint for the frontend to check completion status, which eliminated timeouts entirely and improved perceived performance.