#Flattening your contracts

Hardhat comes with a built-in flatten task that lets you combine the source code of multiple Solidity files.

# Flattening all your files

If you use the flatten task without passing any other arguments, all the Solidity files in your project will be combined:

$ npx hardhat flatten
// Sources flattened with hardhat v2.12.3 https://hardhat.org

// File contracts/Bar.sol

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

contract Bar {}

// File contracts/Qux.sol

...

The result will be printed to stdout. You can create a file with the flattened sources using the > redirection operator:

$ npx hardhat flatten > Flattened.sol

$ cat Flattened.sol
// Sources flattened with hardhat v2.12.3 https://hardhat.org

// File contracts/Bar.sol

...

# Flattening specific files

The flatten task can receive a path to the file you want to flatten:

npx hardhat flatten contracts/Foo.sol

In this case, the result will contain the source code of Foo.sol and all its transitive dependencies (the files that it imports, and the files that those files import, and so on).

You can also use multiple files:

npx hardhat flatten contracts/Foo.sol contracts/Bar.sol

But if Bar.sol is a dependency of Foo.sol, then the result will be the same as in the previous example.

As explained in the previous section, you can redirect the output to some file:

npx hardhat flatten contracts/Foo.sol > Flattened.sol

# Circular dependencies

Projects with circular dependencies cannot be flattened at the moment. If this is something you need, please upvote or comment this issue.