How does the Thank You Page Work
Background
Prior to May 2026, customers only needed to enter their phone number on the Thank You Page (TYP) to be automatically subscribed or enrolled in flows — no further action was required. To make consent more explicit and better support GDPR compliance, we have revised the widget. The TYP now defaults to single opt-in with an explicit checkbox, requiring customers to actively confirm they wish to receive WhatsApp messages rather than being subscribed automatically.
Single or Double opt-in
The Thank You Page can be configured as either single or double opt-in.
Single opt-in is the default behaviour — the customer enters their phone number and checks a box to confirm their consent. The checkbox cannot be pre-enabled; it must be left unchecked by default.
Double opt-in can also be enabled on the Thank You Page. When activated, submitting a phone number triggers our backend to send a one-time 6-digit passcode (OTP) to the customer via WhatsApp. Because entering the code is a deliberate second action, this method is always classified as double opt-in and cannot be configured as single opt-in. The subscription is only completed once the customer enters the code correctly.
The OTP feature is free to enable on the Thank You Page and does not require a Shopify Plus subscription. Please note that each verification message sent may incur an authentication fee charged by Meta. Contact support to get it enabled.
Configuring the Thank You Page
Prerequisites
Shopify integrated with your Universe
The OTP feature enabled on your universe (required only if you wish to configure double opt-in at the end of the purchase Journey)
Before configuring the Thank You Page, decide on your preferred opt-in method:
Single opt-in — You can use an existing single opt-in subscription or navigate to Audiences → Subscriptions to create a new one dedicated to the Thank You Page.
Double opt-in (OTP) — Navigate to Audiences → Subscriptions and create a new Double Opt-in subscription for the Thank You Page. While you can use an existing double opt-in subscription, we recommend creating a dedicated one to make tracking easier. If you are replacing or supplementing an existing single opt-in subscription, please add it to "Accept general opt-ins for order flows" under Advanced Settings in the Shopify Integration to ensure existing contacts can still be enrolled in flows.
Configure TYP in Charles: Navigate to Automation → Thank You Page and click "Create New" to set up a new checkout page, or "Edit" to modify an existing one.
Please note that only single opt-in subscriptions will be displayed if the OTP (double opt-in) feature has not been enabled for your universe. Once enabled, double opt-in subscriptions will also become available, and a Verification Code section will appear on the configuration page.
You can also configure your messages and set your desired languages from this page. Don't forget to hit save.
Configure Checkout UI Widget in Shopify: If you were already using the Thank You Page, the widget is most likely already visible in your Shopify checkout. If not, navigate to Settings → Checkout in Shopify and click "Edit". Click on "Apps" and select the Checkout UI from Charles. Click the "+" button to reveal the "Add to Menu" option, then select "Thank You Page" to add the widget there. Once added, you can place it in either the Main or Order Summary section.
Preview Checkout UI Widget: In Shopify, navigate to Settings → Checkout. Under Configurations, click "Edit". At the top of the editor, use the dropdown to select the Thank You page. Click the three horizontal dots button (⋯) (second from the right) and select "View" to preview how the Checkout UI widget on the TYP will appear to customers.