> **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.

# Create Event Filter \[contract.createEventFilter]

Creates a filter to listen for new event logs emitted by a contract.

Poll the filter with [`Actions.filter.getChanges`](/docs/actions/public/filter/getChanges). Use [`Actions.filter.getLogs`](/docs/actions/public/filter/getLogs) to read the full set.

Call [`Actions.filter.uninstall`](/docs/actions/public/filter/uninstall) when you finish. Viem decodes matching logs with the contract ABI stored by the filter.

## Usage

This example creates a filter to listen for new event logs emitted by a contract.

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

const filter = await client.contract.createEventFilter({
  abi: Abis.erc20,
  eventName: 'Transfer',
})

const logs = await client.filter.getChanges({ filter })
```

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

export const client = Client.create({
  chain: mainnet,
  transport: http(),
}).extend(publicActions())
```
:::

### Standalone Action

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

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

const filter = await Actions.contract.createEventFilter(client, {
  abi: Abis.erc20,
  eventName: 'Transfer',
})

const logs = await Actions.filter.getChanges(client, { filter })
```

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

export const client = Client.create({
  chain: mainnet,
  transport: http(),
})
```
:::

## Recipes

Use a Client method or pass the Client to the standalone action.

### Filtering by Indexed Arguments

Pass `args` to filter logs by the event's indexed arguments.

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

const client = Client.create({ chain: mainnet, transport: http() })
const filter = await Actions.contract.createEventFilter(client, {
  abi: Abis.erc20,
  eventName: 'Transfer',
  args: { // [!code focus]
    from: '0xd8da6bf26964af9d7eed9e03e53415d37aa96045', // [!code focus]
  }, // [!code focus]
})
```

### Listening for All Events in an ABI

Omit `eventName` to decode every event defined on the ABI.

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

const client = Client.create({ chain: mainnet, transport: http() })
const filter = await Actions.contract.createEventFilter(client, {
  abi: Abis.erc20, // [!code focus]
})
```

## Return Value

`Actions.filter.Filter<'event'>`

An event filter typed from the contract ABI. Its `request` function uses the transport that created the filter ID.

## Parameters

### abi

* **Type:** `Abi`

The contract ABI. Matched logs are decoded against it.

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

const client = Client.create({ chain: mainnet, transport: http() })
// ---cut---
const filter = await Actions.contract.createEventFilter(client, {
  abi: Abis.erc20, // [!code focus]
})
```

### address

* **Type:** `Address | Address[]`

Address or list of addresses from which logs originated.

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

const client = Client.create({ chain: mainnet, transport: http() })
const abi = Abis.erc20
// ---cut---
const filter = await Actions.contract.createEventFilter(client, {
  abi,
  address: '0xfba3912ca04dd458c843e2ee08967fc04f3579c2', // [!code focus]
})
```

### args

* **Type:** Inferred from `abi` and `eventName`.

Indexed argument values to filter logs by.

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

const client = Client.create({ chain: mainnet, transport: http() })
const abi = Abis.erc20
// ---cut---
const filter = await Actions.contract.createEventFilter(client, {
  abi,
  eventName: 'Transfer',
  args: { from: '0xd8da6bf26964af9d7eed9e03e53415d37aa96045' }, // [!code focus]
})
```

### eventName

* **Type:** Inferred from `abi`.

Event name to filter and decode logs by. When omitted, every event on the ABI is decoded.

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

const client = Client.create({ chain: mainnet, transport: http() })
const abi = Abis.erc20
// ---cut---
const filter = await Actions.contract.createEventFilter(client, {
  abi,
  eventName: 'Transfer', // [!code focus]
})
```

### fromBlock

* **Type:** `bigint | BlockTag`

Block number or tag after which to include logs.

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

const client = Client.create({ chain: mainnet, transport: http() })
const abi = Abis.erc20
// ---cut---
const filter = await Actions.contract.createEventFilter(client, {
  abi,
  fromBlock: 19_760_000n, // [!code focus]
})
```

### strict

* **Type:** `boolean`
* **Default:** `false`

Whether the logs must match the indexed/non-indexed arguments on the event.

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

const client = Client.create({ chain: mainnet, transport: http() })
const abi = Abis.erc20
// ---cut---
const filter = await Actions.contract.createEventFilter(client, {
  abi,
  eventName: 'Transfer',
  strict: true, // [!code focus]
})
```

### toBlock

* **Type:** `bigint | BlockTag`

Block number or tag before which to include logs.

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

const client = Client.create({ chain: mainnet, transport: http() })
const abi = Abis.erc20
// ---cut---
const filter = await Actions.contract.createEventFilter(client, {
  abi,
  toBlock: 19_760_100n, // [!code focus]
})
```

## Errors

| Error | Description |
| --- | --- |
| `AbiItem.NotFoundError` | The selected event is missing from the runtime ABI. |
| `AbiEvent.FilterTypeNotSupportedError` | `args` includes an indexed tuple or array, which event topic filters do not support. |
| `AbiParameters.InvalidTypeError` | `args` includes an indexed ABI type that the topic encoder does not support. |
| `Address.InvalidAddressError` | `args` includes an invalid indexed address. |
| `Hex.IntegerOutOfRangeError` | `args` includes an indexed integer outside the supported 256-bit range. |
| `Hex.SizeExceedsPaddingSizeError` | An indexed fixed-bytes value exceeds the 32-byte topic size. |