Checkout UI Extension not rendering

Extensions
1

Hi Team,

We have a custom Checkout UI extension that performs several checks based on product metafields and customer metafields. Depending on the result of these checks, the extension is either displayed or hidden.

When the extension is displayed, it requires the customer to provide certain information. If that information is not provided, the order is blocked from being placed.

We are seeing sporadic cases where the required information is not captured at all, which indicates that the extension did not render during checkout. Based on our testing, this appears to happen when the customer has a slow network connection (as suggested here). I was able to reliably reproduce the issue using a 3G connection, where the extension sometimes fails to load.

However, with a normal connection, we are unable to reproduce the issue—even when rebuilding the same cart configuration.

The frequency of these occurrences has been increasing over the past two months. This extension has been live for approximately 1.5 years. Previously, we would see this issue about once per week, but it has now increased to 3–4 occurrences per week.

We are looking for ideas on how to further troubleshoot this behavior or mitigate the risk of the extension not rendering under slow network conditions. Any recommendations or similar experiences would be greatly appreciated.

For reference, the API version in use is 2025-01 (not sure if this is relevant).

Thank you in advance.

2

Hi there,

If missing a specific checkout is that high of a risk there are two ways to solve this issue.

  1. Implement a cart validation function to make sure the customer performs the specific action required based on the conditions

  2. Implement a Shopify Flow that catches these occurrences that slip through the cracks due to this network latency issue

Checkout Extensions were not designed for 100% coverage, that’s what the server side validation functions are for.

3

Hi @Dylan ,

Thank you for your response!

If we are unable to collect the data during checkout, it does not prevent us from fulfilling the order. In those cases, the merchant’s team follows up with the customer directly to collect the required information, and the order is fulfilled once that information is provided. That said, this is not an effective process, as this information ideally should be collected during checkout.

To confirm my understanding of point #1: implementing a cart/checkout validation function would prevent the customer from placing the order if the required data is missing, correct?

We are currently using Shopify Flow to identify and tag these orders when they slip through.

It is just that at this point, there is an assumption that everything is being cause by slow connectivity. You mentioned that Checkout Extensions were not designed for 100% Coverage, do we know the actual % that it was designed to cover?

Thanks again for the guidance.