> For the complete documentation index, see [llms.txt](https://validly.gitbook.io/docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://validly.gitbook.io/docs/validators/build-in-validators/common.md).

# Common

Common built-in validators for multiple data types

### Required

Ensures a value is present, treating it as required. For strings, it optionally allows empty values based on the `allowEmptyStrings` parameter.

### NotEmpty

Ensures the value is not empty. Can be applied to strings or collections.