Sign messages

This guide will teach you how to sign messages using your Smart Wallet. Message signing is a key feature that allows users to authenticate and prove ownership of their wallet without spending gas.

Smart Wallets will generate signatures that can be validated using ERC-1271. If the wallet is an undeployed smart contract account (also known as a counterfactual address), then the signature will be wrapped according to ERC-6492.

Prerequisites

• API key from your dashboard
• A Smart Wallet with an associated signer

What is message signing?

Message signing allows users to:

• Authenticate without spending gas
• Prove ownership of their wallet
• Sign arbitrary data for offchain verification
• Interact with dApps that require signature-based authentication

Smart Wallets support EIP-191 message signing, which is the standard for Ethereum message signing. You may also see EIP-191 referred to as the personal_sign message format.

Text messages

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import { client } from "./client";
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// Sign a simple text message
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const textSignature = await client.signMessage({
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  message: "Hello, world!",
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});
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console.log("Signature over text:", textSignature);

Raw hex messages

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import { client } from "./client";
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// Sign a raw hex message
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const rawSignature = await client.signMessage({
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  message: {
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    raw: "0x48656c6c6f2c20776f726c6421", // "Hello, world!" in hex
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  },
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});
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console.log("Signature over raw data:", rawSignature);

Next steps

Build more:

• Sign typed data
• Send transactions

Troubleshooting:

• Common errors