Shopify · Performance
Shopify Speed & Reliability Overhaul + A/B-Ready Theme Pair
Shopify Performance Engineer (audit, implementation, QA)
Mobile performance program for a US DTC Shopify store (Dawn), delivered in 5 evidence-gated milestones without risking checkout, reviews or tracking.
Highlights
- Render-blocking files 5 → 1; 130 KB of third-party JS removed
- Hero image on phones up to 58% lighter
- Reviews: from "only after a click" to every load (40/40 runs, Safari/iOS fix)
- Matched A/B themes, reviews vs no reviews
- Desktop CLS 0.43 → 0, PageSpeed 98–99
- Duplicate themes, verified backups, 5.0★ review, rehired
How it went
The owner's priorities were clear: checkout first, look second, reviews third, speed fourth. So every change had to prove it broke nothing above it.
The audit found five files blocking the first paint, a hero image sent at full size to every phone, two libraries loaded only for a rotating banner, and a leftover script blocking the store's own reviews.
I removed jQuery and the carousel, served a correctly sized hero image, deferred below-the-fold CSS and fixed the reviews loader. A Safari-only reviews failure was then traced to how WebKit runs removed scripts, and fixed: 40/40 test runs across Safari, Chrome and Firefox, phone and desktop.
For an A/B test I built two themes that differ only in the reviews. When the owner later spotted a desktop layout shift, I traced it to one of my own earlier changes, owned it, and fixed it: CLS 0.43 to 0, confirmed by the owner's own PageSpeed runs (98-99).
Everything ran on duplicate themes, was documented with before/after screenshots, and is backed up as verified, restorable versions.
Details
- Site
- camerastopper.com
- Deliverable
- Case_Study_Shopify_Performance.pdf (7 pages: audit findings, before/after metrics, cross-browser evidence and results)
- Published
- Skills
- Shopify
- Shopify Development
- Page Speed Optimization
- Website Optimization
- Liquid