Cart Drawer vs Product Add-ons & Custom Options: Shopify Performance Comparison
Product Add-ons & Custom Options wins with Grade C vs Grade D — a one-grade performance difference that compounds on mobile devices.
Both apps provide post-purchase upsell and cross-sell functionality for Shopify stores. This page presents StackConflict’s independent lab results for both — measured in a clean-room environment with no other apps installed.
Head-to-Head Metrics
| Metric | Cart Drawer | Product Add-ons & Custom Options | Faster |
|---|---|---|---|
| Overall Grade | D | C | Product Add-ons & Custom Options |
| JS Payload | 792.34 KB | 157.55 KB | Product Add-ons & Custom Options |
| CPU Desktop | 11 ms | 25 ms | Cart Drawer |
| CPU Mobile | 57 ms | 152 ms | Cart Drawer |
| Layout Shift | 0.0 | 0.0 | Cart Drawer |
Mobile CPU measured with 4× CDP throttle (mid-range Android). Tested 2026-05-30.
Product Add-ons & Custom Options — The Faster Option (Grade C)
Product Add-ons & Custom Options scores Grade C with a JS payload of 157.55 KB and 25 ms desktop CPU execution. Mobile CPU: 152 ms. Even as the faster of the two options, merchants on mobile-heavy stores should weigh its impact on their combined app stack.
View full Product Add-ons & Custom Options speed report →
Cart Drawer — The Heavier Option (Grade D)
Cart Drawer scores Grade D with a JS payload of 792.34 KB and 11 ms desktop CPU execution. Mobile CPU: 57 ms. This places it in the heavier half of StackConflict’s benchmark dataset — merchants running mobile-first stores should evaluate whether the feature value justifies the performance tradeoff.
View full Cart Drawer speed report →
When to Choose Cart Drawer
- Its unique feature set has no lighter equivalent in StackConflict’s database
- Your store traffic is predominantly desktop
- You have already removed or lightened other heavy scripts to compensate
When to Choose Product Add-ons & Custom Options
- Its unique feature set has no lighter equivalent in StackConflict’s database
- Your store traffic is predominantly desktop
- You have already removed or lightened other heavy scripts to compensate
Performance Verdict
Winner: Product Add-ons & Custom Options — Product Add-ons & Custom Options wins with Grade C vs Grade D — a one-grade performance difference that compounds on mobile devices.
Both apps carry Grade C — see StackConflict’s full Upsell rankings for lighter alternatives.
About This Test
StackConflict measures each Shopify app in an isolated clean-room environment — a single development store, no other scripts, Playwright-controlled browser. V8 CPU cost is the ScriptDuration delta before and after injection. CLS is captured from the same browser session. Results represent the median of three independent runs with outliers removed.
Data from the StackConflict Lab. Last updated 2026-05-30.