> **Can't find what you're looking for?** Use `search_docs` on the docs MCP server at `https://v3.viem.sh/api/mcp` to find what you need.

# Sign Message \[signMessage]

Calculates an [EIP-191](https://eips.ethereum.org/EIPS/eip-191) signature over a personal message.

* **Local Accounts**: signs locally (no JSON-RPC request).
* **JSON-RPC Accounts**: signs via `personal_sign`.

## Usage

This example calculates an [EIP-191](https://eips.ethereum.org/EIPS/eip-191) signature over a personal message.

:::code-group
```ts twoslash [example.ts]
import { client } from './viem.config'

const signature = await client.signMessage({
  message: 'hello world',
})
// @log: '0xa461f509887bd19e312c0c58467ce8ff8e300d3c1a90b608a760c5b8031...'
```

```ts twoslash [viem.config.ts] filename="viem.config.ts"
import { Account, Client, http, walletActions } from 'viem'
import { mainnet } from 'viem/chains'

export const client = Client.create({
  account: Account.fromPrivateKey('0x…'),
  chain: mainnet,
  transport: http(),
}).extend(walletActions())
```
:::

### Standalone Action

Call `Actions.signMessage` directly by passing the Client as the first argument.

:::code-group
```ts twoslash [example.ts]
import { Actions } from 'viem'
import { client } from './viem.config'

const signature = await Actions.signMessage(client, {
  message: 'hello world',
})
// @log: '0xa461f509887bd19e312c0c58467ce8ff8e300d3c1a90b608a760c5b8031...'
```

```ts twoslash [viem.config.ts] filename="viem.config.ts"
import { Account, Client, http } from 'viem'
import { mainnet } from 'viem/chains'

export const client = Client.create({
  account: Account.fromPrivateKey('0x…'),
  chain: mainnet,
  transport: http(),
})
```
:::

## Recipes

### Sign Raw Bytes

Pass `{ raw }` when the input is already encoded. Viem signs these bytes without applying UTF-8
encoding first.

:::code-group
```ts twoslash [example.ts]
import { Hex } from 'viem/utils'
import { client } from './viem.config'

const signature = await client.signMessage({
  message: { raw: Hex.fromString('hello world') }, // [!code focus]
})
// @log: '0xa461f509887bd19e312c0c58467ce8ff8e300d3c1a90b608a760c5b8031...'
```

```ts twoslash [viem.config.ts] filename="viem.config.ts"
import { Account, Client, http, walletActions } from 'viem'
import { mainnet } from 'viem/chains'

export const client = Client.create({
  account: Account.fromPrivateKey('0x…'),
  chain: mainnet,
  transport: http(),
}).extend(walletActions())
```
:::

### Request a Signature from a Connected Wallet

Use a JSON-RPC Account when a connected wallet holds the signing key. The wallet receives a
`personal_sign` request and prompts the account holder.

:::code-group
```ts twoslash [example.ts]
import { client } from './viem.config'

const signature = await client.signMessage({
  message: 'hello world',
})
// @log: '0xa461f509887bd19e312c0c58467ce8ff8e300d3c1a90b608a760c5b8031...'
```

```ts twoslash [viem.config.ts] filename="viem.config.ts"
import { Client, custom, walletActions } from 'viem'
import { mainnet } from 'viem/chains'
import 'viem/window'

export const client = Client.create({
  account: '0xA0Cf798816D4b9b9866b5330EEa46a18382f251e', // [!code focus]
  chain: mainnet,
  transport: custom(window.ethereum!),
}).extend(walletActions())
```
:::

## Return Value

`Hex`

The signed message.

## Parameters

### account

* **Type:** `Account | Address`
* **Default:** `client.account`

Account (or address) to sign with.

```ts twoslash
import { Account, Actions } from 'viem'
// [!include ~/snippets/docs/reference-client.ts:setup]
// ---cut---
const signature = await Actions.signMessage(client, {
  account: Account.fromPrivateKey('0x…'), // [!code focus]
  message: 'hello world',
})
```

### message

* **Type:** `string | { raw: Hex | Bytes }`

Message to sign. Pass `{ raw }` to sign over raw bytes without UTF-8 encoding.

```ts twoslash
import { Actions } from 'viem'
// [!include ~/snippets/docs/reference-client.ts:setup]
// ---cut---
const signature = await Actions.signMessage(client, {
  message: { raw: '0x68656c6c6f20776f726c64' }, // [!code focus]
})
```

### requestOptions

* **Type:** `{ dedupe?: boolean; signal?: AbortSignal; ... }`

Options forwarded to the `personal_sign` request for a JSON-RPC Account.

```ts twoslash
import { Actions, Client, http } from 'viem'
import { mainnet } from 'viem/chains'

const client = Client.create({ chain: mainnet, transport: http() })
// ---cut---
const controller = new AbortController()
const signature = await Actions.signMessage(client, {
  message: 'hello world',
  requestOptions: { signal: controller.signal }, // [!code focus]
})
```

## Errors

| Error | Description |
| --- | --- |
| `Account.NotFoundError` | No `account` was provided and the client has no account. |