Buy with Prime vs UserWay Accessibility Widget: Shopify Performance Comparison
UserWay Accessibility Widget wins with Grade B vs Grade C — a one-grade performance difference that compounds on mobile devices.
Both apps provide general Shopify store enhancement 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 | Buy with Prime | UserWay Accessibility Widget | Faster |
|---|---|---|---|
| Overall Grade | C | B | UserWay Accessibility Widget |
| JS Payload | 184.43 KB | 112.17 KB | UserWay Accessibility Widget |
| CPU Desktop | 19 ms | 12 ms | UserWay Accessibility Widget |
| CPU Mobile | 121 ms | 83 ms | UserWay Accessibility Widget |
| Layout Shift | 0.0006 | 0.0 | UserWay Accessibility Widget |
Mobile CPU measured with 4× CDP throttle (mid-range Android). Tested 2026-05-30.
UserWay Accessibility Widget — The Faster Option (Grade B)
UserWay Accessibility Widget scores Grade B with a JS payload of 112.17 KB and 12 ms desktop CPU execution. Mobile CPU: 83 ms. It passes every StackConflict threshold for payload, CPU, and layout stability — making it safe to install on any storefront including mobile-first stores where Time-to-Interactive directly impacts conversion.
View full UserWay Accessibility Widget speed report →
Buy with Prime — The Heavier Option (Grade C)
Buy with Prime scores Grade C with a JS payload of 184.43 KB and 19 ms desktop CPU execution. Mobile CPU: 121 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 Buy with Prime speed report →
When to Choose Buy with Prime
- 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 UserWay Accessibility Widget
- You need its specific features and can monitor its mobile impact
- Your other apps are lightweight (Grade A) so there is headroom
- You are on desktop-skewed traffic where CPU cost matters less
Performance Verdict
Winner: UserWay Accessibility Widget — UserWay Accessibility Widget wins with Grade B vs Grade C — a one-grade performance difference that compounds on mobile devices.
Install UserWay Accessibility Widget →
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.