# API Shield WAF Expression Templates
## Generate fallthrough WAF expression template from a set of API hosts
**POST** `/zones/{zone_id}/api_gateway/expression-template/fallthrough`
### Responses
#### 200 Generate fallthrough WAF expression template response
> Data is at `body["result"]`
```json
{
"expression": "*string*",
"title": "*string*"
}
```
#### 4XX Generate fallthrough WAF expression template failure
```json
{
"errors": [
{
"code": "*integer*",
"documentation_url": "*string*",
"message": "*string*",
"source": {
"pointer": "*string*"
}
}
],
"messages": [
{
"code": "*integer*",
"documentation_url": "*string*",
"message": "*string*",
"source": {
"pointer": "*string*"
}
}
],
"result": {},
"success": "*boolean*"
}
```