# ZoneRpcAuthentication.getFields

Returns the 29-byte fixed field suffix for a Zone RPC authentication token.

## Imports

:::code-group
```ts [Named]
import { ZoneRpcAuthentication } from 'ox/tempo'
```

```ts [Entrypoint]
import * as ZoneRpcAuthentication from 'ox/tempo/ZoneRpcAuthentication'
```
:::

## Examples

```ts twoslash
import { ZoneRpcAuthentication } from 'ox/tempo'

const fields = ZoneRpcAuthentication.getFields({
  chainId: 4217000026,
  expiresAt: 1711235160,
  issuedAt: 1711234560,
  zoneId: 26
})
```

## Definition

```ts
function getFields(
  authentication: PartialBy<ZoneRpcAuthentication, 'version'>,
): Fields
```

**Source:** [src/tempo/ZoneRpcAuthentication.ts](https://github.com/wevm/ox/blob/main/src/tempo/ZoneRpcAuthentication.ts#L428)

## Parameters

### authentication

* **Type:** `PartialBy<ZoneRpcAuthentication, 'version'>`

The Zone RPC authentication token.

## Return Type

The fixed 29-byte field suffix.

[`Fields`](/tempo/reference/ZoneRpcAuthentication/types#zonerpcauthenticationfields)