> For the complete documentation index, see [llms.txt](https://docs.armchain.org/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.armchain.org/get-started/quickstart.md).

# Quickstart

Get a Solidity smart contract running on Armchain in just a few minutes. This guide uses Remix IDE and the Armchain Ethers SDK, no complex local setup required.

> **Coming from Ethereum?** The workflow is very similar. The main difference is that Armchain uses ML-DSA44 (post-quantum) signatures instead of ECDSA, so you'll use the Armchain Ethers SDK instead of standard ethers.js for any signing operations.

> **Tooling note**: Hardhat and Foundry do not natively support ML-DSA44 signing. Use **Remix IDE** for contract development and the [**Armchain Ethers SDK**](/developers/overview-1.md) for programmatic interaction.

## Prerequisites

* [Node.js](https://nodejs.org/) v18+
* **Armchain Wallet** browser extension connected to devnet
* Familiarity with Solidity and Ethereum development

## Step 1: Write Your Contract in Remix

1. Open [Remix IDE](https://remix.ethereum.org) in your browser
2. In the **File Explorer**, create a new file: `HelloArmchain.sol`
3. Paste the following contract:

```solidity
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.24;

contract HelloArmchain {
    string public greeting;
    address public owner;

    event GreetingChanged(string oldGreeting, string newGreeting, address changedBy);

    constructor(string memory _greeting) {
        greeting = _greeting;
        owner = msg.sender;
    }

    function setGreeting(string memory _newGreeting) external {
        string memory oldGreeting = greeting;
        greeting = _newGreeting;
        emit GreetingChanged(oldGreeting, _newGreeting, msg.sender);
    }

    function getGreeting() external view returns (string memory) {
        return greeting;
    }
}
```

## Step 2: Compile

1. Open the **Solidity Compiler** tab in Remix (the `<S>` icon)
2. Select compiler version **0.8.24**
3. Set the EVM version to **london** under Advanced Settings
4. Click **Compile HelloArmchain.sol**

## Step 3: Deploy to Armchain

1. Open the **Deploy & Run Transactions** tab in Remix
2. Under **Environment**, select **Injected Provider**. Remix will connect to your Armchain Wallet
3. Make sure your wallet is connected to the **Armchain Devnet** (Chain ID: 55)
4. In the constructor field, enter `"Hello from Armchain!"`
5. Click **Deploy** and confirm the transaction in your wallet

Your contract address will appear in the **Deployed Contracts** panel.

> For local development without a wallet, see [Fakenet Setup](/node-operators/fakenet.md) to run a local Armchain network and use the SDK directly.

## Step 4: Interact with Your Contract

Use the **Armchain Ethers SDK** to interact with your deployed contract from JavaScript or TypeScript.

Install the SDK:

```bash
npm install @armchain-ethersv6/ethers
```

Then interact with your contract:

```typescript
import { JsonRpcProvider, Wallet, Contract } from "@armchain-ethersv6/ethers";

const provider = new JsonRpcProvider("https://www.armchain.org/devnet");
const wallet = new Wallet(process.env.PRIVATE_KEY, provider);

// Paste the ABI from Remix (Compiler tab → ABI button)
const abi = [
  "function getGreeting() view returns (string)",
  "function setGreeting(string) external",
  "event GreetingChanged(string, string, address)"
];

const contract = new Contract("YOUR_CONTRACT_ADDRESS", abi, wallet);

// Read
const greeting = await contract.getGreeting();
console.log("Current greeting:", greeting);

// Write
const tx = await contract.setGreeting("Quantum-safe greetings!");
await tx.wait();
console.log("Greeting updated!");
```

## Alternative: Hardhat + Armchain Ethers SDK

> **⚠ Partial Compatibility**: Hardhat does not natively support ML-DSA44 signing. `npx hardhat compile` works, but Hardhat's built-in accounts and `hre.ethers` signers use ECDSA and **cannot sign Armchain transactions**. All signing must go through `@armchain-ethersv6/ethers`. Deployment scripts, fork testing, and self-funding are **not supported** via standard Hardhat workflows.

Hardhat can be used for **compilation and project structure**:

```bash
mkdir my-armchain-dapp && cd my-armchain-dapp
npm init -y
npm install --save-dev hardhat @nomicfoundation/hardhat-toolbox
npm install @armchain-ethersv6/ethers
npx hardhat init
```

Configure `hardhat.config.js` for Armchain:

```javascript
require("@nomicfoundation/hardhat-toolbox");

module.exports = {
  solidity: {
    version: "0.8.24",
    settings: { evmVersion: "london" },
  },
  networks: {
    armchain: {
      url: "https://www.armchain.org/devnet",
      chainId: 55,
    },
    "armchain-local": {
      url: "http://localhost:4000",
      chainId: 55,
    },
  },
};
```

Compile your contracts:

```bash
npx hardhat compile
```

For deployments, write scripts using `@armchain-ethersv6/ethers` directly instead of `hre.ethers`:

```javascript
// scripts/deploy.js - uses Armchain Ethers SDK for signing, not hre.ethers
import { JsonRpcProvider, Wallet, ContractFactory } from "@armchain-ethersv6/ethers";
import HelloArmchainArtifact from "../artifacts/contracts/HelloArmchain.sol/HelloArmchain.json" assert { type: "json" };

const provider = new JsonRpcProvider("http://localhost:4000");
const wallet = new Wallet(process.env.PRIVATE_KEY, provider);

const factory = new ContractFactory(HelloArmchainArtifact.abi, HelloArmchainArtifact.bytecode, wallet);
const contract = await factory.deploy("Hello from Armchain!");
await contract.waitForDeployment();
console.log("Deployed to:", await contract.getAddress());
```

> **Note**: Do not use `hre.ethers.getSigners()`, `hre.ethers.getContractFactory()`, or `deployer.sendTransaction()`. These all use ECDSA and will fail on Armchain.

## Next Steps

* [Network Configuration](/get-started/network-configuration.md) for RPC endpoints, chain details, and wallet setup
* [Smart Contract Development](/developers/overview.md) for contract patterns and best practices
* [Armchain Ethers SDK](/developers/overview-1.md) for the full SDK reference
* [Understanding PQC](/pqc/overview.md) to learn about the cryptography powering Armchain