Add Postscript SDK to Shopify Plus Checkout

Are you in the right place? Brands on Shopify Plus can add Postscript SDK to their theme code. However, if your brand is on Shopify Plus and has already upgraded to Checkout Extensibility in Shopify, see this article.

If your shop is not on Shopify Plus, see this article for how to enable checkout collection.

To collect SMS subscribers, it's essential that you ensure the correct opt-in language is visible and meets the latest compliance standards. Postscript created our Plus SDK which contains code that adds TCPA-compliant language to your checkout page while still enabling you to collect SMS and email subscribers. Adding Postscript's SDK to your brand's checkout page allows you to:

  • Easily ensure compliant SMS opt-in for all subscribers.
  • Collect SMS consent when the customer selects the Continue to Shipping button.
  • Customize your checkbox label to offer an opt-in incentive, such as a discount.

This article walks through how to add that language and the opt-in checkbox to your checkout page.

Add Compliance Language to Your Shopify Theme

Below, we walk through how to add the Postscript SDK code to your Shopify Plus checkout.

1. Select Online Store in the menu of your Shopify Admin dashboard.

2. Select Themes from the options listed. 

3. Locate your current theme and select the Actions drop-down menu.

4. Select Edit code from the options listed.

5. Select the Layout section to view files related to your layout.

6. Locate and select the checkout.liquid file.

7. Locate the <head> section of the checkout.liquid file.

8. Copy the following code into this section:

<script type="application/javascript" async src=">"></script>

9. Replace the placeholder "YOUR_SHOP_ID_HERE" with your store's Shop ID. You can locate your Shop ID in your Postscript Account Settings.

10. Select Save to save your updated code file.

  Don't see your checkout.liquid file? Reach out to your Shopify Merchant Success Manager (MSM) and request they make it available in your store. You will need to select Add a New Layout and choose Checkout from the drop-down options once your MSM confirms the file is live.

Confirm Your Updated Checkout

Once you've updated your Shopify checkout with the Postscript SDK, you need to test your checkout process.

When testing in Postscript, it's best to use a new or inactive phone number. You can use the same phone number for testing, but you will need to manually unsubscribe the number from your store prior to each test.

For this test, add an item to your cart and proceed to your checkout. Enter the new or inactive phone number in the phone fields at the bottom of the checkout and select the updated opt-in checkbox. Once done, select Continue to shipping.

Shopify Plus Checkout.png

How do you know it works? You can check whether the test phone number you entered is now listed as a subscribed number. Locate the Search field in the side menu of your Postscript dashboard and enter the phone number. If subscribed, it should appear in the drop-down. (7).png

   Tip: You always have the option to reach out to our Support team for help with confirming or double-checking your updated checkout. You can reach them by email at or by selecting the chat box in the lower-right corner of the page.

Remove Old Checkout Language

You can remove your old checkout language once you've confirmed the updated SDK checkout is live.

1. Select Settings in the bottom-left corner of your Shopify Admin dashboard.

2. Select Checkout and accounts on the left-hand side of the Settings menu.

3. Locate the Checkout language section and select Manage checkout language.

4. Locate the section called Checkout Marketing. You can use the search field at the top of the page to search for it.

5. In the field labeled Accept marketing checkbox label, delete your old compliance language and replace it with Keep me up to date on news and exclusive offers via email. Note: To remain compliant, do not mention mobile or phone in this field.

6. Select Save in the top-right corner of the page.

Return to your Settings menu and select Checkout and accounts. This time, locate the Consent for marketing section. We always strongly recommend that you give your customers the option to opt-in to any type of communication from your store, including email. That's why we encourage you to leave the Preselect the sign-up option unselected here.

Screen Shot 2022-11-23 at 3.29.33 PM.png

Once done, select Save in the upper-right corner of the page.

   Tip: Interested in customizing your SMS checkbox language? Check out this article to see how!

Get Support

Have questions? Please feel free to reach out to our wonderful Support team at or via live chat. You can also submit a support request here!

Need ongoing channel strategy guidance? Please fill out this form and we'll connect you to one of our certified partners.

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