# What belongs in a Shopify cart performance checklist?

Source: https://checkoutconversionlab.com/shopify-cart-performance-checklist/

Check that cart content renders in HTML, quantity and remove controls work without heavy blocking scripts, images are sized, totals update reliably, and the checkout action remains clear and responsive.

## Start with the likely cause

Use the gap between TTFB, FCP, LCP, CLS, and INP to narrow the problem before changing code. Keep the template, device, and network conditions consistent.

## Change one thing on a theme copy

Isolate the suspected image, Liquid, CSS, JavaScript, app, or extension cost. A single controlled change makes the result easier to interpret and reverse.

## Verify the whole journey

Repeat the measurement, then test navigation, product selection, cart updates, and checkout handoff. A faster metric is not a win if the storefront task breaks.

## Source

[Shopify developer documentation](https://shopify.dev/docs/storefronts/themes/architecture/templates/cart), accessed September 21, 2026.

## Frequently asked questions

**What should be measured?**
:   Use the metric tied to the suspected cause, then verify the complete task.

**Where should the change be tested?**
:   On a theme copy with repeated conditions.

**When is the work complete?**
:   After the live journey and the repeated measurement pass.