Theme & App Script Optimization for Shopify Core Web Vitals

The Challenge

Project Overview

Vibeszn is a Shopify store that needed Core Web Vitals optimization to improve search rankings and deliver a faster shopping experience for their customers.

The store's theme and third-party apps were creating performance bottlenecks, particularly around LCP and INP. These issues were impacting both organic rankings and the shopping experience on mobile devices.

The Goals

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:

• Eliminate Total Blocking Time on both devices
• Reduce mobile LCP below 2.5s
• Reduce mobile CLS below 0.1

The Solution

Our Approach

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

1. 1

   Performance Audit

   Identified key bottlenecks in theme code and app scripts.

2. 2

   Theme Optimization

   Streamlined Liquid templates and reduced render-blocking resources.

3. 3

   App Script Management

   Deferred and optimized third-party app loading.

4. 4

   Image Optimization

   Implemented proper sizing, formats, and lazy loading.

5. 5

   CWV Validation

   Validated improvements against real user data.

The Results

Outcomes

Core metrics that improved over the duration of the project.

• 100% Mobile TBT Eliminated. Mobile TBT reduced from 890ms to 0ms.
• 53% Mobile LCP Reduction. Mobile LCP dropped from 4.3s to 2.0s.
• 100% Desktop TBT Eliminated. Desktop TBT reduced from 1,490ms to 0ms.

Lessons

Key Takeaways

• Shopify app scripts are often the biggest performance bottleneck.
• Theme-level Liquid optimization delivers consistent improvements across all pages.
• Mobile-first optimization is critical for e-commerce stores.