Back in Stock Alerts vs Privy: Shopify Performance Comparison
Back in Stock Alerts wins with Grade C vs Grade D — a one-grade performance difference that compounds on mobile devices.
Both apps provide email marketing and automation 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 | Back in Stock Alerts | Privy | Faster |
|---|---|---|---|
| Overall Grade | C | D | Back in Stock Alerts |
| JS Payload | 203.34 KB | 2952.99 KB | Back in Stock Alerts |
| CPU Desktop | 4 ms | 223 ms | Back in Stock Alerts |
| CPU Mobile | 27 ms | 974 ms | Back in Stock Alerts |
| Layout Shift | 0.0 | 0.0006 | Back in Stock Alerts |
Mobile CPU measured with 4× CDP throttle (mid-range Android). Tested 2026-05-30.
Back in Stock Alerts — The Faster Option (Grade C)
Back in Stock Alerts scores Grade C with a JS payload of 203.34 KB and 4 ms desktop CPU execution. Mobile CPU: 27 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 Back in Stock Alerts speed report →
Privy — The Heavier Option (Grade D)
Privy scores Grade D with a JS payload of 2952.99 KB and 223 ms desktop CPU execution. Mobile CPU: 974 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 Privy speed report →
When to Choose Back in Stock Alerts
- 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 Privy
- 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: Back in Stock Alerts — Back in Stock Alerts 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 Email Marketing 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.