pmnts

pmnts is a payments focused mobile PWA.

There are several key features:

• Savings (powered by Uniswap V4, Apecoin Staking, Savings DAI, Compound cUSDC)
• P2P based payments
• QR payments

QR based payments offer a novel UX form factor for real world crypto usage, and changes the UX for developers to integrate crypto into their app.

There's also new UX around signing introduced. Approval and transfer operations for the Savings feature can be skipped for instance, all abstracted away into one user interaction.

If the mobile signer has no ETH loaded, another wallet will execute all the transactions on behalf of the signer – in other words, outside of linking another Ethereum account with funds via approval, there's no need to buy or deposit ETH into the Privy signer.

This project is based on the Nextjs and the Privy PWA starter, with a postgres db hosted on Railway. The UI is built with heavy help from the Shadcn UI library.

For tx signing, this is done via Nextjs serverless API routes – although backend signing is skipped if the user has loaded ETH into their Privy wallet – allowing for the whole flow to be more trustless if the user chooses to.

For the contracts, these were written in Solidity, developed in Foundry and deployed to various partner chains like Mantle, Base Goerli, zkEVM testnet, Scroll testnet, and Sepolia. The Apecoin token was bridged over manually as an xERC20.

Github Links: Univ4 referral fee hook: https://github.com/mergd/ref-fee-hook Main contracts repo: https://github.com/mergd/pmnts-ethonline PWA webapp (majority of work here): https://github.com/mergd/qr-pmnts-ethonline/tree/main