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# IPC

## Overview

The [`ipc`](/docs/transports/ipc) transport carries JSON-RPC requests over a local IPC socket. The
socket can be a Unix domain socket or Windows named pipe.

Nodes typically expose this socket on the same machine. Like
[WebSocket](/docs/transports/websocket), IPC supports subscriptions, reconnection, and
resubscription.

It is Node-only, so it is imported from `viem/node` rather than the root entrypoint.

```ts twoslash
import { ipc } from 'viem/node'

const transport = ipc('/tmp/reth.ipc')
```

## Recipes

### Disabling Reconnection

By default the socket reconnects on closure. Pass `reconnect: false` to disable.

```ts twoslash
import { ipc } from 'viem/node'

const transport = ipc('/tmp/reth.ipc', { reconnect: false }) // [!code focus]
```

### Tuning Reconnection

Pass a `reconnect` object to control how often the socket retries and the delay before reconnecting.

```ts twoslash
import { ipc } from 'viem/node'

const transport = ipc('/tmp/reth.ipc', {
  reconnect: { maxRetries: 10, minReconnectionDelay: 2_000 }, // [!code focus]
})
```

### Tuning Keep-Alive

Pass a `keepAlive` object to tune the interval used for connection health checks.

```ts twoslash
import { ipc } from 'viem/node'

const transport = ipc('/tmp/reth.ipc', {
  keepAlive: { interval: 30_000 }, // [!code focus]
})
```

### Restricting RPC Methods

Use `methods` to allow or deny specific RPC methods for this transport.

```ts twoslash
import { ipc } from 'viem/node'

const transport = ipc('/tmp/reth.ipc', {
  methods: { include: ['eth_call', 'eth_chainId'] }, // [!code focus]
})
```

### Configuring Retries

Set `retryCount` and `retryDelay` to control how many times failed requests retry and the base backoff between attempts.

```ts twoslash
import { ipc } from 'viem/node'

const transport = ipc('/tmp/reth.ipc', {
  retryCount: 5, // [!code focus]
  retryDelay: 200, // [!code focus]
})
```

### Setting a Request Timeout

Set `timeout` to limit how long a JSON-RPC request can take before it fails.

```ts twoslash
import { ipc } from 'viem/node'

const transport = ipc('/tmp/reth.ipc', { timeout: 20_000 }) // [!code focus]
```

## `ipc`

Creates an IPC JSON-RPC transport (Node only).

### Usage

```ts twoslash
import { ipc } from 'viem/node'

const transport = ipc('/tmp/reth.ipc')
```

### Parameters

#### path

* **Type:** `string`

The path to the IPC socket, such as `/tmp/reth.ipc`.

```ts twoslash
import { ipc } from 'viem/node'
// ---cut---
const transport = ipc('/tmp/reth.ipc') // [!code focus]
```

#### options.keepAlive

* **Type:** `boolean | { interval?: number }`
* **Default:** `true`

Whether (and how often) to send keep-alive messages.

```ts twoslash
import { ipc } from 'viem/node'
// ---cut---
const transport = ipc('/tmp/reth.ipc', {
  keepAlive: { interval: 30_000 }, // [!code focus]
})
```

#### options.key

* **Type:** `string`
* **Default:** `'ipc'`

Transport key.

```ts twoslash
import { ipc } from 'viem/node'
// ---cut---
const transport = ipc('/tmp/reth.ipc', {
  key: 'ipc', // [!code focus]
})
```

#### options.methods

* **Type:** `{ include?: string[] } | { exclude?: string[] }`

RPC methods to include or exclude.

```ts twoslash
import { ipc } from 'viem/node'
// ---cut---
const transport = ipc('/tmp/reth.ipc', {
  methods: { include: ['eth_call', 'eth_chainId'] }, // [!code focus]
})
```

#### options.name

* **Type:** `string`
* **Default:** `'IPC JSON-RPC'`

Transport name.

```ts twoslash
import { ipc } from 'viem/node'
// ---cut---
const transport = ipc('/tmp/reth.ipc', {
  name: 'IPC JSON-RPC', // [!code focus]
})
```

#### options.reconnect

* **Type:** `boolean | { maxRetries?: number; minReconnectionDelay?: number; maxReconnectionDelay?: number; reconnectionDelayGrowFactor?: number; minUptime?: number; connectionTimeout?: number; maxEnqueuedMessages?: number }`
* **Default:** `true`

Whether (and how) to reconnect on socket closure. `maxRetries` caps reconnection attempts (default `Infinity`); `minReconnectionDelay`/`maxReconnectionDelay` bound the backoff window.

```ts twoslash
import { ipc } from 'viem/node'
// ---cut---
const transport = ipc('/tmp/reth.ipc', {
  reconnect: { maxRetries: 10, minReconnectionDelay: 2_000 }, // [!code focus]
})
```

#### options.retryCount

* **Type:** `number`
* **Default:** `3`

Max retries per request.

```ts twoslash
import { ipc } from 'viem/node'
// ---cut---
const transport = ipc('/tmp/reth.ipc', {
  retryCount: 5, // [!code focus]
})
```

#### options.retryDelay

* **Type:** `number`
* **Default:** `150`

Base delay (ms) between retries.

```ts twoslash
import { ipc } from 'viem/node'
// ---cut---
const transport = ipc('/tmp/reth.ipc', {
  retryDelay: 200, // [!code focus]
})
```

#### options.timeout

* **Type:** `number`
* **Default:** `10_000`

Request timeout (ms).

```ts twoslash
import { ipc } from 'viem/node'
// ---cut---
const transport = ipc('/tmp/reth.ipc', {
  timeout: 20_000, // [!code focus]
})
```

### Return Value

`Transport<'ipc', { getRpcClient, subscribe }>`

An IPC transport. The instance exposes `getRpcClient()` for the live client and `subscribe()` for JSON-RPC subscriptions.