Kiwi Sizing vs Moonshot AI: Shopify Performance Comparison
Moonshot AI wins with Grade C vs Grade D — a one-grade performance difference that compounds on mobile devices.
Both apps provide personalization and product recommendations 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 | Kiwi Sizing | Moonshot AI | Faster |
|---|---|---|---|
| Overall Grade | D | C | Moonshot AI |
| JS Payload | 521.05 KB | 232.81 KB | Moonshot AI |
| CPU Desktop | 70 ms | 54 ms | Moonshot AI |
| CPU Mobile | 331 ms | 127 ms | Moonshot AI |
| Layout Shift | 0.0 | 0.0 | Kiwi Sizing |
Mobile CPU measured with 4× CDP throttle (mid-range Android). Tested 2026-05-31.
Moonshot AI — The Faster Option (Grade C)
Moonshot AI scores Grade C with a JS payload of 232.81 KB and 54 ms desktop CPU execution. Mobile CPU: 127 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 Moonshot AI speed report →
Kiwi Sizing — The Heavier Option (Grade D)
Kiwi Sizing scores Grade D with a JS payload of 521.05 KB and 70 ms desktop CPU execution. Mobile CPU: 331 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 Kiwi Sizing speed report →
When to Choose Kiwi Sizing
- 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 Moonshot AI
- 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: Moonshot AI — Moonshot AI 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 Personalisation 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 2026-05-31.