> ## Documentation Index
> Fetch the complete documentation index at: https://docs.hedera.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Remix IDE

> Write, compile, and deploy Solidity contracts to Hedera testnet from your browser.

Remix is an open-source Solidity IDE that runs in the browser. It compiles, debugs, and deploys without anything installed locally. Because Hedera is EVM-compatible, the same Remix workflow you'd use against Ethereum works against Hedera once MetaMask is pointed at the JSON-RPC relay.

The rest of this page walks through that workflow end-to-end.

## Prerequisites

<CardGroup cols={2}>
  <Card title="MetaMask configured for Hedera Testnet" icon="wallet" href="/evm/quickstart/setup-metamask">
    Network `Hedera Testnet`, RPC `https://testnet.hashio.io/api`, Chain ID `296`.
  </Card>

  <Card title="Testnet HBAR" icon="faucet" href="/evm/quickstart/get-test-hbar">
    A small amount of testnet HBAR to pay for deployment.
  </Card>
</CardGroup>

## Step 1: Open Remix

Go to [remix.ethereum.org](https://remix.ethereum.org). Accept the default workspace if it asks. The left sidebar gives you a File Explorer, the Solidity Compiler, and the Deploy & Run Transactions panel.

## Step 2: Write a contract

In File Explorer, create `contracts/HelloHedera.sol` and paste:

```solidity theme={null}
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.22;

contract HelloHedera {
    string public message = "Hello, Hedera!";

    event MessageUpdated(address indexed by, string newMessage);

    function updateMessage(string memory newMessage) public {
        message = newMessage;
        emit MessageUpdated(msg.sender, newMessage);
    }
}
```

## Step 3: Compile

1. Open the **Solidity Compiler** tab.
2. Set the compiler version to `0.8.22` (or anything that satisfies the `pragma`).
3. Click **Compile HelloHedera.sol**. Green checkmark means success.

<Tip>
  Turn on **Auto compile** in the compiler settings so Remix recompiles every save. Saves a click on every edit.
</Tip>

## Step 4: Connect MetaMask

1. Switch to the **Deploy & Run Transactions** tab.
2. In the **Environment** dropdown, pick **Injected Provider - MetaMask**.
3. MetaMask asks to connect. Approve.
4. The **Network** field should read `Custom (296) network`. That's Hedera testnet.

If it shows a different network, switch MetaMask to **Hedera Testnet** from its own network dropdown.

## Step 5: Deploy

1. Confirm the **CONTRACT** dropdown shows `HelloHedera`.
2. Click the orange **Deploy** button.
3. MetaMask prompts to confirm the transaction. Review the HBAR gas fee and click **Confirm**.
4. The contract appears under **Deployed Contracts** at the bottom of the panel after a few seconds.

## Step 6: Interact with the contract

Expand the deployed contract under **Deployed Contracts**. You get a blue read-only **message** button that returns the current value at no gas cost, and an orange **updateMessage** field that writes a new value (this one costs gas).

Click **message** to see the initial value. Type something into **updateMessage** and call it. Confirm the MetaMask popup. Click **message** again to see the new value.

## Step 7: View on HashScan

Copy the contract address from the **Deployed Contracts** panel and open:

```text theme={null}
https://hashscan.io/testnet/contract/<your-address>
```

HashScan shows the deploy transaction, the bytecode, and any subsequent calls. If you want the source code readable on HashScan, [verify the contract](/evm/development/verifying) with the same Solidity file you used in Remix.

## When to reach for Remix

| Use case                                 | Tool                                                                       |
| ---------------------------------------- | -------------------------------------------------------------------------- |
| Quick prototyping, single contract       | Remix                                                                      |
| Reproducible deploys, tests, scripts     | [Hardhat](/evm/tools/hardhat/index) or [Foundry](/evm/tools/foundry/index) |
| Guided UI for ERC-20 / ERC-721 templates | [Contract Builder](/evm/tools/contract-builder)                            |
| Cross-chain libraries (LayerZero, CCIP)  | Hardhat. Remix's import resolution gets shaky                              |

Remix is the right tool when you're learning, poking at one contract, or doing throwaway experiments. Once you want version control, a test suite, or repeatable CI deploys, move to Hardhat or Foundry.

## See also

<CardGroup cols={2}>
  <Card title="Contract Builder" icon="hammer" href="/evm/tools/contract-builder">
    Browser-based deploys without writing any Solidity yourself.
  </Card>

  <Card title="Hardhat" icon="hard-hat" href="/evm/tools/hardhat/index">
    Move your Remix contract into a Hardhat project for tests and CI.
  </Card>
</CardGroup>