I am trying to verify on hardhat an nft-tutorial by chainlink but am unable to. I have converted most of the code to hardhat compatible. The contract address on Rinkeby is 0xA4630A1f2DaC2474d7397E7e8F3A41Bd574C1f9d. I want to deploy using Hardhat not Truffle. Here is the link to the repo

Here is my command

npx hardhat verify --network rinkeby 0xA4630A1f2DaC2474d7397E7e8F3A41Bd574C1f9d "0xb3dCcb4Cf7a26f6cf6B120Cf5A73875B7BBc655B", "0x01BE23585060835E02B77ef475b0Cc51aA1e0709", "0x2ed0feb3e7fd2022120aa84fab1945545a9f2ffc9076fd6156fa96eaff4c1311"

Based on the hardhat docs, I should be able to run:

npx hardhat verify --network rinkeby DEPLOYED_CONTRACT_ADDRESS "Constructor argument 1" "Argument 2"

Getting this error when running the above code:

TypeError: Cannot read property 'contracts' of undefined

Sometimes I also get:

TypeError: Cannot read property 'engines' of undefined
  • You won't be able to verify pure truffle code with hardhat, but yet, I am running into similar errors here. I'll shop this link around. Mar 23, 2021 at 19:50
  • Have always wanted to try out Hardhat. Recently I have been unable to deploy to testnets because of some errors(ESOCKETTIMEDOUT error) which Alchemy and Infura teams were suspecting to be caused by Truffle. And for this nft tutorial specifically I deployed successfully with Hardhat where Truffle failed. Going forward what is the best practice, since I will be conceiving and implementing my projects(not following a tutorial like this case), is the hardhat workflow not as simple as having the solidity contracts in the relevant folder, and using the Hardhat workflow for deployment and beyond?
    – HallonDev
    Mar 24, 2021 at 4:50
  • HallonDev, can you add your repo here? Mar 25, 2021 at 13:29

1 Answer 1


Your code has comma separators while passing the arguments and docs doesn't say so. Not sure but just verify that this isn't the issue here.

Anyways, hardhat allows to pass arguments through file too. Hardhat Docs

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