How can I achieve a dynamic redirect for a Webflow form depending on the customer's selection of plan and ad spend, when using an external subscription service for payment?

To achieve a dynamic redirect for a Webflow form based on the customer's selection of plan and ad spend when using an external subscription service for payment, you can follow these steps:

1. Set up your form: First, create a form in Webflow with necessary form fields to capture customer's selection of plan and ad spend. Also, add a hidden field to store the payment service URL.

2. Configure the form action: In the form settings, set the action to a custom URL, which will be a server-side script or a webhook that you create. This URL will handle the form submission and perform the redirection based on the user's selection.

3. Create a server-side script or webhook: You'll need to create a server-side script (PHP, Node.js, etc.) or use a webhook service (such as Zapier) to process the form submission and redirect the user dynamically. This script will be responsible for gathering form data, constructing the appropriate URL for payment, and redirecting the user accordingly.

4. Retrieve form data: Within the server-side script or webhook, retrieve the form data submitted by the user. You can access this data in the request object's body or query parameters depending on how you set up your form action.

5. Construct the payment URL: Based on the customer's selection of plan and ad spend, you'll need to construct the payment URL specific to your external subscription service. This URL should include any necessary query parameters or form data required by the subscription service to pre-fill the payment form with the selected plan and ad spend.

6. Redirect the user: Once you have the payment URL, use a server-side redirect (e.g., `header('Location: payment_url')` in PHP) to redirect the user to the payment page.

Note: The implementation details will vary depending on the programming language or webhook service you choose. Ensure you follow the specific documentation for your chosen platform to handle form data and perform the redirection.

By following these steps, you can achieve a dynamic redirect for a Webflow form based on the customer's selection of plan and ad spend when using an external subscription service for payment.