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Overview

This guide shows you how to sign messages with your EVM wallet. Message signing is commonly used for authentication, nonce verification, and data integrity checks.

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Prerequisites

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Basic Message Signing

The Node SDK is stateless — every sign call requires walletMetadata (and externalServerKeyShares if you store them in your own vault). Load both from where you persisted them at wallet creation time. 
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: 'your-password', // required if wallet was created with backUpToDynamic: true
});

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

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Simple Message Signing

Whether you need to provide externalServerKeyShares depends on how you created your wallet: If you created your wallet with backUpToDynamic: true, the SDK can recover the shares from backup using password — you can omit externalServerKeyShares: 
// ✅ Simple signing - SDK recovers shares from backup via password
const signature = await evmClient.signMessage({
  message: 'Hello, World!',
  walletMetadata,
  password: 'your-password',
});

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With Manual Backup

If you created your wallet with backUpToDynamic: false, you must provide the cached externalServerKeyShares: 
// Retrieve your stored key shares from your secrets vault.
const externalServerKeyShares = await vault.read(`wallet:${accountAddress}/shares`);

const signature = await evmClient.signMessage({
  message: 'Hello, World!',
  walletMetadata,
  externalServerKeyShares, // required for manual-backup wallets
});
Password handling notes:
  • If your wallet was created without a password (backUpToDynamic: false, no password), omit the password parameter.
  • If your wallet was created with a password (backUpToDynamic: true), pass it.
  • See signMessage reference for full details.
Password Handling Notes:
  • If your wallet was created without a password, omit the password parameter
  • If your wallet was created with a password, you must provide it for all operations
  • The password parameter is always optional in the API, but required if the wallet is password-protected

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Common Use Cases

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Authentication

const nonce = Date.now().toString();
const message = `Sign this message to authenticate: ${nonce}`;
const signature = await evmClient.signMessage({
  message,
  walletMetadata,
  externalServerKeyShares,
  password: 'your-password',
});

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Data Integrity

const data = { userId: 123, action: 'transfer', amount: '100' };
const message = JSON.stringify(data);
const signature = await evmClient.signMessage({
  message,
  walletMetadata,
  externalServerKeyShares,
  password: 'your-password',
});

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Next Steps