how can I verify a proxy contract on polygon amoy testnet with Hardhat? When I run the verify command, I get the following error, so I can't verify:

Etherscan API call failed with status 404, response: {"code":404,"msg":"","error_code":"404","error_message":"","detailMsg":"","data":{"timestamp":1712163082073,"status":404,"error":"Not Found","trace":"java.lang.NullPointerException: Cannot invoke \"String.toLowerCase()\" because the return value of \"java.util.Map.get(Object)\" is null...

I have prepared the minimal code needed to reproduce the error here. https://github.com/keit0728/cannot-verify-on-amoy

It would be helpful if you could run this command and check it.

npx hardhat run scripts/deploy.js --network polygonAmoy

1 Answer 1


I believe the reason is that hardhat proxy cannot be verified this way currently. Tbh they should really allow hardhat and maybe we should push for a feature request on their discord.


"Currently, verifying proxy contracts through Hardhat is not supported. If you need to verify proxy contracts, you will need to manually verify them through a browser."

  • It looks like they are working on adding this for OKLInk so at this point, we're just waiting for it to be a thing.
    – bearsworth
    Commented Apr 19 at 20:46

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