> Markdown version of [Form Validation](https://vaadin.com/docs/v24/building-apps/forms-data/add-form/validation). Section index: [llms.txt](https://vaadin.com/docs/v24/building-apps/llms.txt)

# Form Validation

Form validation is a fundamental aspect of building robust and user-friendly applications. It ensures that the data entered by users meets the expected format and business rules before it’s processed or stored. Effective validation helps safeguard the **security** and **integrity** of your application. It also enhances the **user experience** by providing immediate feedback and preventing common input errors.

To learn more about validation from a broader architectural perspective, see the [Data Consistency](https://vaadin.com/docs/v24/building-apps/deep-dives/application-layer/consistency.md) deep dive.

> **Tip: Part of a Series**
>
> This is part 2 of the **Add a Form** series. It builds on the concepts introduced in the [Fields & Binding](https://vaadin.com/docs/v24/building-apps/forms-data/add-form/fields-and-binding.md) guide.

Vaadin provides built-in support for form validation in both Flow and Hilla:

- [Form Validation in Flow](https://vaadin.com/docs/v24/building-apps/forms-data/add-form/validation/flow.md)

- [Form Validation in Hilla](https://vaadin.com/docs/v24/building-apps/forms-data/add-form/validation/hilla.md)