Vebay

This project is a secondhand marketplace built with Next.js that uses Worldcoin’s Mini App to verify that each user is a real human through WorldID, with proofs stored on World Chain. It integrates vLayer to extract and verify item details—such as name, price, and purchase date—from Amazon email receipts, using email proofs to confirm that the emails are authentic and haven't been forged. This helps prevent sellers from listing items with incorrect prices or false purchase dates. Once verified, the email proof is stored on an Optimism Sepolia smart contract. Each listing on the marketplace includes a WorldID check and a linked vLayer proof, giving buyers clear information about the item’s origin and purchase history.

We built this project using Next.js for both the frontend and backend, with Worldcoin’s Mini App SDK to handle WorldID verification and prove that each user is a real person, storing that proof on World Chain. For verifying item authenticity, we used vLayer to parse Amazon email receipts and extract the item name, price, and purchase date, then stored those proofs on an Optimism Sepolia smart contract. The user flow involves first verifying their identity with Worldcoin, then connecting their email through vLayer to fetch a receipt, and finally creating a listing tied to that proof. We used Viem to read and write to the blockchain, and kept the UI simple to focus on the verification layers.