> ## Documentation Index
> Fetch the complete documentation index at: https://docs.formbase.dev/llms.txt
> Use this file to discover all available pages before exploring further.

# Input Validation

> Validate data before submitting to Formbase.

Formbase stores whatever data you submit. It does not enforce a schema or validate field values on the server, so you should validate input in your frontend or in a backend proxy.

Use client-side validation for UX and server-side validation when data integrity matters.

<Steps>
  <Step title="Add client-side rules">
    ```html theme={null}
    <input name="email" type="email" required />
    <input name="age" type="number" min="18" max="120" />
    ```

    Native HTML constraints are the fastest way to reduce invalid submissions.
  </Step>

  <Step title="Validate on the server (optional)">
    If you need stricter validation, submit to your own API first, validate, then forward to Formbase.
  </Step>
</Steps>

<Callout type="note">
  Anyone can bypass browser validation or submit directly to the endpoint. Use server-side validation for critical workflows.
</Callout>