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

# signMessage

> Signs a message using the specified EVM wallet

## Function Signature

```typescript theme={"system"}
signMessage(params: {
  message: string;
  walletMetadata: WalletMetadata;
  password?: string;
  externalServerKeyShares?: ServerKeyShare[];
}): Promise<string>
```

## Description

Signs a message using the EVM wallet identified by the supplied `walletMetadata`. The SDK is stateless — every call requires `walletMetadata`. If the wallet was created with `backUpToDynamic: true`, supply the `password` so the SDK can recover shares from backup when `externalServerKeyShares` is omitted.

<Warning>
  When you pass `externalServerKeyShares` (the caller-supplied path), `walletMetadata.externalServerKeySharesBackupInfo` must also be present — `signMessage` throws if shares are supplied but backup metadata is missing. The full `walletMetadata` returned from `createWalletAccount` / `importPrivateKey` already includes it; identity-only metadata from `fetchWalletMetadata` will be rejected.
</Warning>

## Parameters

### Required Parameters

* **`message`** (`string`) - The message to sign
* **`walletMetadata`** ([`WalletMetadata`](/node/reference/types/wallet-metadata)) - Non-sensitive wallet metadata persisted from `createWalletAccount()` / `importPrivateKey()`. The wallet's address comes from `walletMetadata.accountAddress`.

### Optional Parameters

* **`password`** (`string`) - Required if the wallet was created with `backUpToDynamic: true`. Used for backup decryption when `externalServerKeyShares` is not provided.
* **`externalServerKeyShares`** ([`ServerKeyShare[]`](/node/reference/types/server-key-share)) - Caller-supplied plaintext shares. If omitted, the SDK recovers from backup using `password`.

## Returns

* **`Promise<string>`** - The serialized signature as a hex string

## Example

```typescript theme={"system"}
import { authenticatedEvmClient } from './client';

const evmClient = await authenticatedEvmClient();

// Load the metadata + shares you persisted at creation time.
const walletMetadata = JSON.parse(await redis.get(`wallet:${accountAddress}`));
const externalServerKeyShares = await vault.read(`wallet:${accountAddress}/shares`);

const signature = await evmClient.signMessage({
  message: 'Hello, World!',
  walletMetadata,
  externalServerKeyShares,
  password: 'user-password',
});

console.log('Message signed:', signature);
```

## Error Handling

```typescript theme={"system"}
try {
  const signature = await evmClient.signMessage({
    message: 'Hello world',
    walletMetadata,
    externalServerKeyShares,
    password: 'user-password',
  });
  console.log('Message signed successfully');
} catch (error) {
  console.error('Failed to sign message:', error);
}
```

## Security Considerations

* **Message Validation**: Always validate message content before signing
* **Key Share Security**: Keep external server key shares secure
* **Session Management**: Implement proper session management
* **Password Protection**: Use strong passwords for wallet encryption

## Related Functions

* [`signTypedData()`](/node/reference/evm/sign-typed-data) - Sign EIP-712 typed data
* [`signTransaction()`](/node/reference/evm/sign-transaction) - Sign a transaction instead of a message
* [`verifyMessageSignature()`](/node/reference/evm/verify-message-signature) - Verify a message signature