> ## 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.

# Dynamic URL Parameters

> Pass submitted values in the redirect URL.

Sometimes your thank-you page needs context about what the user submitted. Because the data is already available in the browser, you can build query parameters and redirect after a successful Formbase submission.

This is a client-side pattern that works well for simple personalization.

<Steps>
  <Step title="Submit the form">
    Post the form data to Formbase and treat a `303` response as success.
  </Step>

  <Step title="Build the redirect URL">
    ```js theme={null}
    const formData = new FormData(formElement);

    const response = await fetch('https://formbase.dev/s/YOUR_FORM_ID', {
      method: 'POST',
      body: formData,
      redirect: 'manual',
    });

    if (response.status === 303 || response.ok) {
      const params = new URLSearchParams({
        name: String(formData.get('name') || ''),
        plan: String(formData.get('plan') || ''),
      });

      window.location.href = `/thanks?${params.toString()}`;
    }
    ```

    The redirect becomes something like `/thanks?name=Chris&plan=pro`.
  </Step>
</Steps>

<Callout type="note">
  If you need the server response, submit from a server action and return the data to the client.
</Callout>