# Expression Template

# Fallthrough

## Generate fallthrough WAF expression template from a set of API hosts

`client.apiGateway.expressionTemplate.fallthrough.create(FallthroughCreateParamsparams, RequestOptionsoptions?): FallthroughCreateResponse`

**post** `/zones/{zone_id}/api_gateway/expression-template/fallthrough`

Creates an expression template fallthrough rule for API Shield. Used for configuring default behavior when no other expression templates match.

### Parameters

- `params: FallthroughCreateParams`

  - `zone_id: string`

    Path param: Identifier.

  - `hosts: Array<string>`

    Body param: List of hosts to be targeted in the expression

### Returns

- `FallthroughCreateResponse`

  - `expression: string`

    WAF Expression for fallthrough

  - `title: string`

    Title for the expression

### Example

```node
import Cloudflare from 'cloudflare';

const client = new Cloudflare({
  apiToken: process.env['CLOUDFLARE_API_TOKEN'], // This is the default and can be omitted
});

const fallthrough = await client.apiGateway.expressionTemplate.fallthrough.create({
  zone_id: '023e105f4ecef8ad9ca31a8372d0c353',
  hosts: ['{zone}.domain1.tld', 'domain2.tld'],
});

console.log(fallthrough.expression);
```

#### Response

```json
{
  "errors": [
    {
      "code": 1000,
      "message": "message",
      "documentation_url": "documentation_url",
      "source": {
        "pointer": "pointer"
      }
    }
  ],
  "messages": [
    {
      "code": 1000,
      "message": "message",
      "documentation_url": "documentation_url",
      "source": {
        "pointer": "pointer"
      }
    }
  ],
  "result": {
    "expression": "(cf.api_gateway.fallthrough_detected)",
    "title": "Fallthrough Expression for [zone.domain.tld]"
  },
  "success": true
}
```

## Domain Types

### Fallthrough Create Response

- `FallthroughCreateResponse`

  - `expression: string`

    WAF Expression for fallthrough

  - `title: string`

    Title for the expression