This Priceless CFD project can be seen as an "optimistic" CFD that is also leveraged, and fully backed by collateral. Should the CFD contract exceed the price boundary, then a settlement request can be submitted. That request can also be disputed (usually by bots), and everyone is incentivized to report back the correct value of the underlying in order to prevent being penalized.
This project uses React + Next.js for the frontend, Truffle to compile the contracts, Solidity for the contract source code, and a bunch of code from UMA to mimic their "priceless" system, e.g.
The bot is written in Node.js using Ethers.js with a pub/sub method to listen to events.