x402bay
A marketplace for digital goods where every purchase is paid in USDC over the x402 payment protocol.
x402bay is a small marketplace for digital goods that uses x402 for payments.
x402 is Coinbase’s take on the old HTTP 402 Payment Required status code. When you hit the download for something you haven’t paid for, the server answers with a 402 and a price, your wallet pays in USDC, and the request goes through. x402bay was my attempt at building a whole store around that flow, done over a couple of days in November 2025.
Features
- List digital items with a description, images and a price in USDC
- Pay for and download items through x402, with no checkout page in between
- Sign in with your Ethereum wallet (Sign-In with Ethereum)
- Search, categories, likes, and editing or deleting your own listings
It ran on Base Sepolia testnet, so nobody spent real money on it, and the hosted version isn’t up anymore.
Tech Stack
- Next.js and React with Tailwind and shadcn/ui
- Coinbase x402 (
x402-nextandx402-fetch) for payments - RainbowKit, wagmi and viem for wallets, with NextAuth and SIWE for sign-in
- MongoDB Atlas for listings and files