← All apps Email Marketing Klaviyo vs Mailchimp
🔬 Lab Findings 🔧 Stack Builder
⏳ Pending
?
Klaviyo
Data pending
★ 4.6 · 2,802 reviews
Under Review
VS
⏳ Pending
?
Mailchimp
Data pending
★ 4.8 · 1,239 reviews
Under Review
Metric Klaviyo Mailchimp
Overall Grade B A
JS Payload 39.58 KB 0.11 KB
CPU Desktop Pending ⏳ Pending ⏳
CPU Mobile Pending ⏳ Pending ⏳
Layout Shift 0.0005 0.0006
Merchant Rating ★ 4.6 (2,802) ★ 4.8 (1,239)

Klaviyo vs Mailchimp: Shopify Performance Comparison

Data pending for Klaviyo — our scanner captured only the async loader stub for this app. Full bundle metrics are being collected from live Shopify storefronts. Once available, this page will show a complete head-to-head comparison.

Both Klaviyo and Mailchimp provide email marketing and automation functionality for Shopify stores.

What We Know: Mailchimp (Benchmarked)

Mailchimp has been measured in StackConflict’s clean-room lab:

MetricMailchimp
Overall GradeA
JS Payload0.11 KB
CPU Desktop3 ms
CPU Mobile9 ms (0.0s)
Layout Shift0.0006

Grade A means Mailchimp passes every StackConflict threshold — safe to install on any storefront including mobile-first stores.

View full Mailchimp speed report →

Pending: Klaviyo

StackConflict’s scanner detected that Klaviyo uses an async JavaScript loader — a small stub that only initialises its full bundle on a real, authenticated Shopify storefront. This means our lab environment captured the tiny stub file only, not the production bundle that actually runs on live stores.

We are collecting real bundle data by scanning public Shopify storefronts. Once captured, the head-to-head metrics for Klaviyo will appear here automatically.

View Klaviyo on Shopify App Store →

About This Test

StackConflict measures each Shopify app in an isolated clean-room environment — a Playwright-controlled browser with no other scripts installed. V8 CPU cost is the ScriptDuration delta measured before and after bundle injection. Mobile CPU applies the standard 4× Lighthouse slowdown factor.


Mailchimp data from the StackConflict Lab (2026-05-30). Klaviyo data pending.