BillGenie

Backend FastAPI server handling secure PayPal API requests and local testing.
Secure REST API backend built with Python FastAPI.
Responsive React frontend featuring a quick 'Pay Now' option.
Seamless payment routing via the PayPal Developer Sandbox.
Instant payment verification and user redirection upon success.

Inspiration We wanted to simplify B2B transactions. Creating professional invoices and collecting payments usually requires multiple tools and manual effort. BillGenie brings everything together by using AI to generate bills from simple text and integrating PayPal for instant, secure transactions.

What it does BillGenie allows users to enter raw billing details, which our system instantly converts into a professional invoice. It automatically attaches a secure PayPal checkout link. The client can simply click the 'Pay Now' button and complete the transaction smoothly via PayPal.

How we built it Frontend: React JS for a fast, responsive user interface.

Backend: Python FastAPI to handle REST endpoints, generate payment links, and manage webhooks.

Payment Integration: PayPal Developer Sandbox and REST APIs for secure checkout and order creation. We strictly managed environment variables to keep client credentials completely secure.

Challenges we ran into Integrating the PayPal checkout flow with our custom FastAPI backend was initially tricky. We faced challenges in securely managing the OAuth tokens and ensuring the React frontend stayed in sync with the backend webhooks during the payment redirection process.

Accomplishments that we're proud of Successfully integrating the end-to-end PayPal checkout flow with real-time transaction verification on our FastAPI server without any lag.

What we learned We learned a lot about secure payment gateway architecture. Working extensively with the PayPal Developer Sandbox taught us how to handle API authentication, test sandbox transactions effectively, and process webhook payloads in FastAPI to verify payments in real-time.

What's next for BillGenie Adding multi-currency support, subscription billing options, and automated email invoicing.