Justmint

[ Problem ]

• There’s no system to provide appropriate rewards to brand’s fan

While many customers are passionate about spending money on a specific brand both online and offline, they often don't receive fair benefits in proportion to their contributions.

• There’s no interoperability in current coupon system

What If you only have a coupon from McDonald’s but wants to eat at BurgerKing, you can sell the McDonald’s coupon and buy a Burger King coupon?

[ Solution ]

We provide an NFT coupon solution that enables interoperability with Web 2.0 coupon systems. Users can receive benefit NFTs generated based on their purchase history, both online and offline. Also can sell&buy them in an interoperable marketplace.

[ Functions ]

• Embedded Non-custodial wallet and paymasters

Our target users are those who have no prior experience with Web3, so we integrated features such as non-custodial wallet that is generated during the first social login process and gas fee delegation through ERC-4337 paymasters module into our service.

*Why we also support EOA and CA? : There was a method to have a central EOA verify UserOperation for wallet generation, but we believed that it would compromise decentralization. Therefore, we included EOA generation process but introduced an additional AA to enable fee delegation. For those who do not have coins immediately available, we will activate the ERC-4337 paymasters module to have someone else pay on their behalf.

• Issue dynamic NFT and accumulate benefits

• Integrate them and collect all the benefits in a one NFT

• Transfer to metamask with fee delegation and engage in secondary trading

In this project, we implemented a contract wallet using ERC-4337. NFT deploying, minting, and transfer to external wallets are possible on the EVM-based chain, and the gas fee is paid through the account abstraction paymaster. We also used React and Express to design the frontend and backend in typescript for connect web2 and blockchain.