Shopify Checkout API Exensibility for Basic, Advance Store plans

[sheeraz]

Hello,
i need Assistance from experts regarding the Shopify Checkout API or Thank-you page, I am developing an app and want to display message alerts on the checkout page, Based on my understanding of the shopify documentation, this extensibility feature is only available on Shopify Plus, However I am looking to implement this feature for basic and advance plan Shopify stores as well.

If anyone has knowledge about the checkout API or Thank-you page, please guide 
Thank you.

[dexter845 · Accepted solution]

You cannot do that in shopify basic and advanced plans. Checkout customizations are only available for shopify plus plans.
In shopify plus, you can install checkout blocks app and add these alerts without any coding.

[sheeraz]

As Per Shopify Update, they are committed that on 31 December 2024, the additional Script Section will be discontinued, so how can we operate the
the thing we are running which may work for the order thank you page or others..