Common Ninja vs Convertcart: Shopify Performance Comparison
Both apps score Grade C — Common Ninja has the edge with 38 ms vs 39 ms desktop CPU execution.
Both apps provide all-in-one conversion optimization 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 | Common Ninja | Convertcart | Faster |
|---|---|---|---|
| Overall Grade | C | C | Tie |
| JS Payload | 166.14 KB | 386.62 KB | Common Ninja |
| CPU Desktop | 38 ms | 39 ms | Common Ninja |
| CPU Mobile | 145 ms | 147 ms | Common Ninja |
| Layout Shift | 0.0006 | 0.0 | Convertcart |
Mobile CPU measured with 4× CDP throttle (mid-range Android). Tested 2026-05-30.
Common Ninja — The Faster Option (Grade C)
Common Ninja scores Grade C with a JS payload of 166.14 KB and 38 ms desktop CPU execution. Mobile CPU: 145 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 Common Ninja speed report →
Convertcart — The Heavier Option (Grade C)
Convertcart scores Grade C with a JS payload of 386.62 KB and 39 ms desktop CPU execution. Mobile CPU: 147 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 Convertcart speed report →
When to Choose Common Ninja
- 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 Convertcart
- 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
Result: Comparable — Both apps score Grade C — Common Ninja has the edge with 38 ms vs 39 ms desktop CPU execution.
Both apps carry Grade C — see StackConflict’s full All In One 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.