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

# Sign Message with ethers.js

> Sign and recover messages for authentication using ethers.js.

# Sign Message with ethers.js

Sign and recover messages for authentication using ethers.js.

Sign and recover messages for authentication using ethers.js.

## Explanation

signMessage prefixes the message with Ethereum-specific bytes to prevent signing arbitrary transactions. verifyMessage recovers the signer address. signTypedData provides EIP-712 structured data signing for better UX and security.

## Code

```javascript theme={null}
import { ethers } from "ethers";

const wallet = new ethers.Wallet(privateKey);

// Sign a message
const message = "Sign in to MyDApp";
const signature = await wallet.signMessage(message);
console.log("Signature:", signature);

// Recover the signer address
const recovered = ethers.verifyMessage(message, signature);
console.log("Recovered:", recovered);
console.log("Match:", recovered === wallet.address);

// Sign typed data (EIP-712)
const domain = {
  name: "MyDApp",
  version: "1",
  chainId: 1,
};
const types = {
  Mail: [
    { name: "from", type: "string" },
    { name: "contents", type: "string" },
  ],
};
const value = { from: "Alice", contents: "Hello!" };
const typedSig = await wallet.signTypedData(domain, types, value);
```

***

**Canonical knowledge ID:** `code-example:sign-message-ethers`