# Smart Contract Verification

A quick guide on how to verify your contracts on Harmony.

<https://explorer.harmony.one/verifycontract>

Right now, we support verification only for one single solidity file - therefore, before deployment and verification, you will need to flatten all solidity sources to one file.

## 1. Flatten your solidity files (only for multiple files)

To flatten your solidity files we recommended to use <https://www.npmjs.com/package/truffle-flattener>

```jsx
npm install truffle-flattener -g

truffle-flattener <solidity-files>
```

Or you can use any other flattener lib

## 2. Deploy contract to Harmony

To more easy verification we recommend to deploy contract with Harmony Remix <https://docs.harmony.one/home/developers/deploying-on-harmony/using-remix/deployment-using-remix>

## 3. Verify contract

You can verify your contract here <https://explorer.harmony.one/verifycontract>

![](https://3781397247-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LlEOlYqEG_GKuO5Rehq%2Fsync%2Fe07d5a6583b46bafda36d1d9e524f06716917f57.png?generation=1626954921544532\&alt=media)

Important to use correct params (the same like on deploy):

* Contract address
* Contract name
* Compiler version
* Optimizer
* Chain Type (mainnet or testnet)
* Sources
* Imported libs

Then click **Submit** button

If all parameters are correct - you should to see `Success` message, or `Error` if bytecodes don't equal

On Success case - you contract will verify and you will see all contract details on contract explorer page

![](https://3781397247-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LlEOlYqEG_GKuO5Rehq%2Fsync%2Fb96a5a138da7cafe5d85f62ce83837dbb30acfc2.png?generation=1626954921610178\&alt=media)

## 4. Verify contract with constructor arguments (for contracts that were created with constructor parameters)

<https://docs.soliditylang.org/en/develop/abi-spec.html>

To get ABI-encoded constructor arguments you can ue this service: <https://abi.hashex.org>

Example for Harmony Remix:

1 - click ABI to copy it ![image](https://user-images.githubusercontent.com/57394565/126634721-b3762b14-9e43-4313-b6f6-5e2c5126e1c2.png)

2 - paste ABI to <https://abi.hashex.org> form and click parse ![image](https://user-images.githubusercontent.com/57394565/126634847-5f2917ef-ee72-41d6-b246-401b1b9b5b0d.png)

3 - paste your constuctor arguments and click Copy ![image](https://user-images.githubusercontent.com/57394565/126634955-2b458846-540e-4d56-94a1-ce9c26cf3a03.png)

4 - paste encoded constructor arguments to verify form field ![image](https://user-images.githubusercontent.com/57394565/126635142-570cd58e-0f44-4af6-98f3-0b9b8d6095d9.png)