Prime Choice Select

Prime Choice Select is blockchain payment application that automatically selects the best blockchain given the requirements of the payment.


As a story, I tried to withdraw $10 in Ethereum last week and there was going to be a $7 gas fee charge to do so. This isn’t sustainable for small businesses and at scale, so we wanted to make a solution (as a smart contract) that could help merchants invoice for different purchases and enable the buyer to select the token that offers the best transaction value. Payment and invoicing solutions such as Stripe exist, but skim more off the top of every transaction without the benefits of a distributed/managed ecosystem. Prime Choice Select is a blockchain application that helps automatically select the best blockchain to facilitate a given transaction based on the requirements of the payment. Allow merchants to retain more revenue for themselves by optimizing for transaction cost. Every payment is issued as a separate contract that can be completed by a given buyer. We’re an aggregator of layer 2 protocols and we consult all the different providers to determine in real time which network is the cheapest to facilitate a transaction. If the transaction is subscription based or user has recurring payments, we recommend the user leverage layer 2, otherwise we delegate the payment within layer1 (metamask) directly. We can choose the most efficient token to transact in either case.

Prime Choice Select showcase

How it's made

Primechoice Select is a blockchain application deployed using HardHat and React for the website. User authentication and account management is handled using either Torus or MetaMask. This authentication grant is used by ZkSync to power the layer2 payment for subscription based invoices. Payment requests are managed by an Ethereum smart contract built in solidity, which uses Chainlink and Tellor data providers to quote an accurate conversion rate for a given protocol transaction. Every invoice is deployed as a separate contract agreement between an owner and a buyer. The app uses Cairo to prove that a given protocol is the best for a transaction given the information provided from the layer 2 protocol aggregators.The app uses zkSync for enabling layer 2 payments and getting the fee quotes for the different protocols to determine the best one to use at a given point in time. The contract is also deployed on a SKALE endpoint (as a proof of concept) for larger merchants that would want to control the payment ecosystem by using their own separate / secure chain.

Technologies used