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Foundry

To verify your Foundry contracts, you can use Foundry's verify-contract to verify contracts on Lineascan.

You'll need to get a Lineascan (Linea instance of Etherscan) API key by creating an account at https://lineascan.build/myapikey.

Verify your smart contract​

note

These instructions verify using the Linea instance of Etherscan, which currently does not support Yul. If you would like to verify using Blockscout, please use the API URLs referenced here.

Verify a contract that has already been deployed​

If you want to verify a contract that has already been deployed, you can use the following commands:

forge verify-contract --etherscan-api-key LINEASCAN_API_KEY --verifier-url https://api.lineascan.build/api CONTRACT_ADDRESS path_to_contract:contract_name --watch

You should see something a little like this:

Start verifying contract 0x8de6e9b6c774c8b7aba587ed84e5ad0a45837b16 deployed on mainnet

Submitting verification for [src/Counter.sol:Counter] "0x8dE6e9b6c774c8B7AbA587ED84E5AD0A45837b16".
Submitted contract for verification:
        Response: OK
        GUID: `ynnfyvwcqev9i5xr1urdqt9kdwx4zkurvpu7rgh2ywmyp22dpy`
        URL:
        https://etherscan.io/address/0x8de6e9b6c774c8b7aba587ed84e5ad0a45837b16
Contract verification status:
Response: `NOTOK`
Details: `Pending in queue`
Contract verification status:
Response: `OK`
Details: `Pass - Verified`
Contract successfully verified

Verify a contract upon creation​

If you want to verify a contract as it is being deployed for the first time, you can use the following commands:

forge create --rpc-url https://linea.infura.io/v3/INFURA_API_KEY src/Counter.sol:Counter --private-key YOUR_PRIVATE_KEY --verify --verifier-url https://api.lineascan.build/api --etherscan-api-key LINEASCAN_API_KEY

You can check that it was verified correctly by navigating to the testnet block explorer or the mainnet block explorer and pasting in the deployed contract address.

Using .env and foundry.toml to store etherscan information​

If you don't want to paste your keys inline and have multiple Etherscan API keys to manage, you can use .env and foundry.toml to set up custom configurations.

Assuming you followed the instructions to create a .env file here, add your Lineascan API key to the file:

LINEASCAN_API_KEY=YOUR_LINEASCAN_API_KEY

Then, run:

source .env

Finally, modify foundry.toml to include the Etherscan configurations:

[etherscan]
linea-testnet = { key = "${LINEASCAN_API_KEY}", url = "https://api-sepolia.lineascan.build/api" }
linea-mainnet = { key = "${LINEASCAN_API_KEY}", url = "https://api.lineascan.build/api" }

Then, to verify your smart contracts, you can simply run:

forge verify-contract --chain linea-mainnet path_to_contract:contract_name --watch
info

Learn more about different configurations for verifying your smart contracts here and here.