E-Commerce Speed Optimization
Every 100ms faster, ~1% more conversions
A high-traffic online retailer
A retailer with 12M monthly visitors was failing Core Web Vitals across the catalog. Mobile LCP was over 4 seconds on the products customers actually viewed. Marketing kept buying more traffic that bounced before checkout. I ran a focused two-month engagement: image pipeline rebuild, edge caching for the catalog, frontend bundle surgery, and database work on the product-detail query. Conversion went up, bounce went down, and the marketing team saw the same paid traffic perform 23% better with no creative changes.
This is a representative architecture study based on real project patterns. Specific metrics and client details have been generalized to protect confidentiality.
Results
What changed, in numbers
The metrics the engagement is measured by.
1.4s
LCP
from 4.2s on mobile PDP
+23%
Conversion Rate
improvement
-18%
Bounce Rate
reduction on mobile
+$2.1M
Revenue
annual revenue increase
Challenge
What was broken
Mobile users were bouncing before they ever saw a product image. Core Web Vitals were red across the board. The CDN was misconfigured to bypass cache on personalized headers, the product images were unoptimized originals served at native resolution, and the JavaScript bundle included an analytics library twice. Each fix sounded boring; together they were millions of dollars of revenue.
Solution
The shape of the fix
A layered performance program: image optimization pipeline, CDN edge caching with proper invalidation, code splitting and bundle hygiene, database query optimization, and CI-enforced Web Vitals budgets so the gains stick.
Approach
How I tackled it
The concrete moves that took the project from broken to shipped.
Mapped the performance budget to actual revenue impact so prioritization was business-driven
Rebuilt the image pipeline with responsive sources, modern formats, and edge transformation
Fixed the CDN configuration so the catalog and PDP routes were edge-cached with surgical invalidation
Code-split the JavaScript bundle and removed three duplicated analytics libraries
Optimized the product-detail query with covering indexes and a Redis read-through cache
Wrote Web Vitals budgets into CI to keep regressions out
Outcomes
What shipped, and what it changed
Measured results from the engagement, told as a story rather than a scoreboard.
Reduced mobile LCP from 4.2s to 1.4s on product detail pages
Lifted conversion rate by 23% with no marketing or creative changes
Reduced bounce rate by 18% on mobile
Drove approximately $2.1M in incremental annual revenue at current traffic levels
Cut origin egress costs by 30% via better edge caching
Stack
Technologies used
Linked entries open the technology page with related studies, playbooks, and notes.
Services
How I helped
The specific services involved in this engagement. Each links to a deeper breakdown.
Lessons
What I would tell the next team
The takeaways I carry into every similar engagement.
Performance is a revenue lever, not a vanity metric. Frame it that way and budget gets approved
Image and CDN configuration produce most of the wins on most e-commerce sites
If the budget is not in CI, the gains will be gone in two quarters
Related
Other studies you might recognize
Engagements with overlapping problem shapes, industries, or stacks.
Have a similar challenge?
If any of this looks like the project on your desk, the conversation is the cheapest part. You can also browse other e commerce work or the full service list.