# How to get constructor parameters from deployed code

By [N00b21337](https://paragraph.com/@n00b21337) · 2023-10-09

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To actually get constructor parameters you will need to get transaction details and see what was “data” that was sent or if you are using etherscan you can go to”Input Data” field and see all the bytecode there. So I will take this transaction as example

[https://goerli.etherscan.io/tx/0xf15cfeb9be64058ba3680a7095ca045bb7cdddc85e318921a297de36f77e48b0](https://goerli.etherscan.io/tx/0xf15cfeb9be64058ba3680a7095ca045bb7cdddc85e318921a297de36f77e48b0)

and use its bytecode to dissect constructor parameters. We need to go the end of the code and find this part of code

this `0033` is the last opcode that was used before adding the constructor info. 00 means STOP and 33 means CALLER, after that, we have 4 parameters that are four addressed used for this contract constructor, each of them left padded to 32 bytes.

This is what was used in hardhat when deploying and it matches the above bytecode

        args = [
          '0xCb07bf0603da228C8ec602bf12b973b8A94f9bac',
          '0xF5147D56502C80004f91FB4112d6812CddE8eDE3',
          '0xefC5Ead3188402eCC951DB45827F6e0F99B67a25',
          '0xb1C7F17Ed88189Abf269Bf68A3B2Ed83C5276aAe',
        ];
    

So this part where there are constructor parameters on-chain, it can only be found in the transaction when the contract was deployed, you won’t find it in init bytecode or in the deployed bytecode which we talked about here.

[https://mirror.xyz/n00b21337.eth/tNVuQii\_z\_D-2zyFnou9Yh2Hu0U6LajweFgC4WGfI0Y](https://mirror.xyz/n00b21337.eth/tNVuQii_z_D-2zyFnou9Yh2Hu0U6LajweFgC4WGfI0Y)

So if you want to find this code and where it starts you could make a DIFF of init bytecode and bytecode used in deployment transaction creation and you will get this block of code. You could also try to just find

    0033   // Somewhere it Was said that in older contract this was 0029, didnt confirm
    

by the end of the bytecode in contract creation and anything after that will be constructor arguments.

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*Originally published on [N00b21337](https://paragraph.com/@n00b21337/how-to-get-constructor-parameters-from-deployed-code)*