Import (Solidity Code Example)

You can import local and external files in Solidity.

‍

Local

Here is our folder structure.

├── Import.sol
└── Foo.sol

‍

Foo.sol

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.26;

struct Point {
    uint256 x;
    uint256 y;
}

error Unauthorized(address caller);

function add(uint256 x, uint256 y) pure returns (uint256) {
    return x + y;
}

contract Foo {
    string public name = "Foo";
}

‍

Import.sol

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.26;

// import Foo.sol from current directory
import "./Foo.sol";

// import {symbol1 as alias, symbol2} from "filename";
import {Unauthorized, add as func, Point} from "./Foo.sol";

contract Import {
    // Initialize Foo.sol
    Foo public foo = new Foo();

    // Test Foo.sol by getting it's name.
    function getFooName() public view returns (string memory) {
        return foo.name();
    }
}

‍

External

You can also import from GitHub by simply copying the url.

// https://github.com/owner/repo/blob/branch/path/to/Contract.sol
import "https://github.com/owner/repo/blob/branch/path/to/Contract.sol";

// Example import ECDSA.sol from openzeppelin-contract repo, release-v4.5 branch
// https://github.com/OpenZeppelin/openzeppelin-contracts/blob/release-v4.5/contracts/utils/cryptography/ECDSA.sol
import "https://github.com/OpenZeppelin/openzeppelin-contracts/blob/release-v4.5/contracts/utils/cryptography/ECDSA.sol";