Verifying Contracts

Overview

Starknet Foundry sncast supports verifying Cairo contract classes with the sncast verify command by submitting the source code to a selected verification provider. Verification provides transparency, making the code accessible to users and aiding debugging tools.

The verification provider guarantees that the submitted source code aligns with the deployed contract class on the network by compiling the source code into Sierra bytecode and comparing it with the network-deployed Sierra bytecode.

For detailed CLI description, see verify command reference.

⚠️ Warning Please be aware that submitting the source code means it will be publicly exposed through the provider's APIs.

Verification Providers

Walnut

Walnut is a tool for step-by-step debugging of Starknet transactions. You can learn more about Walnut here walnut.dev. Note that Walnut requires you to specify the Starknet version in your Scarb.toml config file.

Example

First, ensure that you have created a Scarb.toml file for your contract (it should be present in the project directory or one of its parent directories). Make sure the contract has already been deployed on the network.

Then run:

$ sncast \
    verify \
    --class-hash 0x031966c9fe618bcee61d267750b9d46e3d71469e571e331f35f0ca26efe306dc \
    --contract-name SimpleBalance \
    --verifier walnut \
    --network sepolia
Output: 

    You are about to submit the entire workspace code to the third-party verifier at walnut.

    Important: Make sure your project does not include sensitive information like private keys. The snfoundry.toml file will be uploaded. Keep the keystore outside the project to prevent it from being uploaded.

    Are you sure you want to proceed? (Y/n): Y

command: verify
message: Contract verification has started. You can check the verification status at the following link: https://app.walnut.dev/verification/status/77f1d905-fdb4-4280-b7d6-57cd029d1259.

📝 Note Contract name is a part after the mod keyword in your contract file. It may differ from package name defined in Scarb.toml file.