Circuitscan is a circuit verifier explorer. Like verified contracts, a verified circuit verifier allows users to interact with applications directly if the frontend becomes unusable as well as ensures that the deployed source code matches the expected source code.

Provide the necessary transparency for ZK apps so that users can trust their blockchain interactions

Circuit verifier Solidity contracts verified on Etherscan are opaque to the viewer. There's no way to quickly check that they match the source code on Github. When users can see this match, they can be sure that there's no backdoors inserted clandestinely.

Verified contracts on etherscan also come into play when a dapp's frontend becomes unusable. For a zk app with a missing frontend, Circuitscan provides a tool for generating proofs so that users never have to worry about being locked out.

Developers use a CLI to submit their circom sources to the verification server just like how Hardhat and Foundry submit deployed contracts to Etherscan. The frontend catalogs all verified submissions with source code and proving keys available for usage.