E-CommerceNext.jsStripePerformance

E-Commerce Platform Redesign

End-to-end redesign and rebuild of a multi-vendor e-commerce platform — cutting checkout drop-off by 34% and boosting mobile conversion by 2.1×.

Overview

A regional marketplace with 400+ vendors needed a complete overhaul. The original platform had a 68% cart abandonment rate on mobile, a checkout flow spread across 7 steps, and zero design consistency across vendor storefronts.

The goal: reduce friction, unify the visual language, and ship a mobile-first experience that vendors could customise without breaking the brand.

Problem

User research surfaced three critical failure points:

  1. Trust gap — product pages lacked social proof and had inconsistent image quality across vendors.
  2. Checkout friction — 7-step checkout with no guest option and no saved payment methods.
  3. Performance — LCP of 8.4s on 4G; images were unoptimised and served without a CDN.

Process

Discovery & Research

  • Moderated usability tests with 12 participants across mobile and desktop
  • Heatmap and session recording analysis (2 weeks, 40,000 sessions)
  • Competitor benchmark: Shopify, Zalando, Amazon checkout flows

Design

  • Component library in Figma: 80+ components, 4 spacing scales, 3 brand tiers
  • Streamlined checkout: 3 steps → single-page accordion with inline validation
  • Vendor storefront system: locked brand chrome, customisable hero + accent colour

Engineering

  • Migrated from a PHP monolith to Next.js App Router + tRPC API
  • Stripe Payment Element replaced the custom card form — PCI scope reduced to SAQ-A
  • Cloudinary CDN + automatic WebP/AVIF conversion; images lazy-loaded with blur placeholders

Results

MetricBeforeAfterChange
Mobile conversion rate1.4%2.9%+107%
Cart abandonment (mobile)68%45%−34%
LCP (4G median)8.4s1.9s−77%
Checkout completion time4m 12s1m 48s−57%

Tech Stack

Next.js 15 · TypeScript · Tailwind CSS · Stripe · tRPC · Prisma · PostgreSQL · Cloudinary · Figma


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