# Page block validators

> For the complete documentation index, see [llms.txt](https://doc.ibexa.co/en/saas/llms.txt).

Set up rules for validating Page block content.

Validators check values passed to Page block attributes. The following block validators are available:

- `required` - checks whether the attribute is provided
- `regexp` - validates attribute according to the provided regular expression
- `not_blank` - checks whether the attribute isn't left empty
- `not_blank_richtext` - checks whether a `richtext` attribute isn't left empty
- `content_type` - checks whether the selected content types match the provided values
- `content_container` - checks whether the selected content item is a container

> **Note: Note**
>
> Don't use the `required` and `not_blank` validators for `richtext` attributes. Instead, use `not_blank_richtext`.

For each validator you can provide a message that displays in the Page Builder when an attribute field doesn't fulfill the criteria.

Additionally, for some validators you can provide settings under the `ibexa_fieldtype_page.blocks.<block_name>.validators.regexp.options` [configuration key](https://doc.ibexa.co/en/saas/administration/configuration/configuration/#configuration-files), for example:

```yaml
email:
    type: string
    name: E-mail address
    validators:
        regexp:
            options:
                pattern: '/^\S+@\S+\.\S+$/'
            message: Provide a valid e-mail address
```