# Submit your contract to explorer

Once verified, a smart contract or token contract's source code becomes publicly available and verifiable. This creates transparency and trust. Plus, it's easy to do!

There are two ways to verify source code:

* [Via explorer](https://docs.u2u.xyz/services/explorer/smart-contract-verification/via-explorer)
* [Via Hardhat](https://docs.u2u.xyz/services/explorer/smart-contract-verification/via-hardhat-plugin)

In this tutorial we only focus on Hardhat.

## Verify

In the last section, we have deployed `Lock` contract on Nebulas testnet:

{% code overflow="wrap" %}

```
Lock with 0.001U2U and unlock timestamp 1696615281 deployed to 0x8D51395C76C34d0e11178c1F7EE3219B4b958e30
```

{% endcode %}

To verify the contract source code with Hardhat, below is the command:

```
npx hardhat verify --network NETWORK DEPLOYED_CONTRACT_ADDRESS [ARG_1 ARG_2 ...]
```

* `NETWORK`: You need to provide which network you have used, eg. `nebulas`
* `DEPLOYED_CONTRACT_ADDRESS`: Where the contract is deployed at, eg. `0x8D51395C76C34d0e11178c1F7EE3219B4b958e30`
* `[ARG_1 ARG_2 ...]`: Arguments that passed to the contructor when the contract is deployed, eg. `unlockTime`

Let's verify it:

{% code overflow="wrap" %}

```
npx hardhat verify --network nebulas 0x8D51395C76C34d0e11178c1F7EE3219B4b958e30 1696615281
```

{% endcode %}

It will result:

```
Successfully submitted source code for contract
contracts/Lock.sol:Lock at 0x8D51395C76C34d0e11178c1F7EE3219B4b958e30
for verification on the block explorer. Waiting for verification result...

Successfully verified contract Lock on the block explorer.
https://testnet.u2uscan.xyz/address/0x8D51395C76C34d0e11178c1F7EE3219B4b958e30?tab=contract
```