PageSpeed Matters
    PageSpeed Matters
    Speed Optimization

    Stencil Theme & Product Catalog Optimization for BigCommerce Store

    E-Commerce · < 10 Employees · BigCommerce

    72%

    Mobile LCP Reduction

    88%

    Mobile TBT Reduction

    57%

    Mobile SI Reduction

    Project Overview

    Liz Mathe runs a BigCommerce store with a large product catalog. They needed speed optimization to improve the shopping experience and handle their extensive product pages efficiently.

    With a large amount of products, the store's category and product pages were loading slowly. BigCommerce's platform constraints required creative approaches to optimization.

    Goals & Objectives

    The primary goal of this project was to improve Google's Core Web Vitals, site speed, and overall user experience and usability.

    Our primary goals were to:

    • Reduce mobile LCP significantly
    • Eliminate layout shift across devices
    • Improve mobile performance score above 80
    Company Name
    Liz Mathe
    Company Size
    < 10 Employees
    Industry
    E-Commerce
    Platform
    BigCommerce

    Outcomes:

    Core metrics that improved over the duration of the project.

    72%

    Mobile LCP Reduction

    Mobile LCP dropped from 15.6s to 4.4s — a 72% improvement.

    88%

    Mobile TBT Reduction

    Mobile TBT reduced from 170ms to just 20ms.

    57%

    Mobile SI Reduction

    Mobile Speed Index improved from 6.8s to 2.9s — a 57% improvement.

    Before vs After

    Before

    MetricScore
    Mobile Perf Score56
    Desktop Perf Score85
    Mobile FCP6.1s
    Desktop FCP1.0s
    Mobile LCP15.6s
    Desktop LCP1.1s
    Mobile TBT170ms
    Desktop TBT20ms
    Mobile CLS0.058
    Desktop CLS0.002
    Mobile SI6.8s
    Desktop SI1.2s

    After

    MetricScore
    Mobile Perf Score85
    Desktop Perf Score85
    Mobile FCP2.1s
    Desktop FCP0.6s
    Mobile LCP4.4s
    Desktop LCP0.8s
    Mobile TBT20ms
    Desktop TBT0ms
    Mobile CLS0
    Desktop CLS0
    Mobile SI2.9s
    Desktop SI1.2s

    Our Approach

    A systematic, step-by-step process tailored to Liz Mathe's needs.

    1

    BigCommerce Audit

    Analyzed platform-specific performance constraints and opportunities.

    2

    Theme Optimization

    Optimized Stencil theme templates for faster rendering.

    3

    Product Image Optimization

    Optimized product images across the entire catalog.

    4

    Script Management

    Deferred and minimized third-party scripts.

    5

    Category Page Optimization

    Improved load times for product listing pages.

    Key Takeaways

    BigCommerce requires platform-specific optimization strategies.

    Large product catalogs need image optimization at scale.

    Category page performance directly impacts product discovery and sales.

    Latest Case Studies

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    Speed performance gauge showing optimized score