PWA Performance That Achieves Sub-Second Loading on 3G Connections

Akamai found that every 100ms of latency costs 7% in conversions. Portent shows 1-second sites convert at 3x the rate of 5-second sites. We optimize PWA performance through service worker caching, code splitting, lazy loading, and CDN deployment to achieve sub-second Time to Interactive on mobile networks.

7%

conversion loss per 100ms of additional latency, making PWA performance optimization directly tied to revenue through faster loading and cached repeat visits

Akamai, 2017

PWA Performance Optimization

Progressive web app performance optimization with service worker caching strategies, code splitting, lazy loading, image optimization, and CDN deployment for sub-second loading.
Smartphone displaying popular social media apps like Instagram, Pinterest, Twitter, and Snapchat.

What's Included

Everything you get with our PWA Performance Optimization

Caching Strategy Optimization

Service worker cache audit and optimization with precaching for critical assets, runtime caching with appropriate strategies per resource type, and cache size management

Bundle and Asset Optimization

Code splitting, tree shaking, lazy loading, image compression with WebP and AVIF, font subsetting, and critical CSS extraction to minimize initial payload

Core Web Vitals Tuning

LCP, FID, CLS, and TTFB optimization with Lighthouse auditing, real user monitoring, and specific fixes for each metric across mobile and desktop

Our PWA Performance Optimization Process

1

Performance Audit

We run Lighthouse audits, analyze Web Vitals from real user data, profile the service worker cache hit rate, and identify the specific bottlenecks causing slow loads. We prioritize fixes by conversion impact.

2

Caching Strategy Optimization

We audit the service worker caching configuration, optimize precache lists, tune runtime cache strategies per resource type, implement cache versioning, and add cache size limits to prevent storage bloat.

3

Bundle and Asset Optimization

We implement code splitting at route boundaries, configure tree shaking, convert images to WebP/AVIF, subset fonts, inline critical CSS, and lazy load below-the-fold content. Every byte is justified.

4

Monitoring and Verification

We set up real user monitoring for Core Web Vitals, configure performance budgets that alert on regressions, and verify improvements in Lighthouse and field data. We document the performance gains.

Key Benefits

Sub-second loading on mobile networks

Code splitting, lazy loading, and asset optimization reduce first-visit payloads to the minimum needed for the current page. Users on 3G connections see interactive content in under one second instead of staring at a loading spinner.

100ms repeat loads from service worker cache

Precached app shells and runtime-cached assets load from local storage on repeat visits. No network round-trip required. Users experience instant loading regardless of whether they are on Wi-Fi, cellular, or completely offline.

Core Web Vitals that pass Google's thresholds

LCP under 2.5 seconds, FID under 100ms, CLS under 0.1. Google uses Core Web Vitals as a ranking factor, and optimized PWAs pass all three thresholds. Better performance means better search rankings and more organic traffic.

Research & Evidence

Backed by industry research and proven results

Online Retail Performance

Every 100ms of latency costs 7% in conversions, and service worker caching eliminates network latency entirely on repeat visits

Akamai (2017)

Page Load and Conversion

A 1-second site converts at 3x the rate of a 5-second site, and PWA optimization techniques like app shell caching achieve sub-second loads even on slow networks

Portent (2022)

Frequently Asked Questions

What is a good Lighthouse score for a PWA?

We target 90 or above on Performance, Accessibility, Best Practices, and SEO, plus passing all PWA-specific criteria. A perfect 100 on Performance is achievable for content-focused PWAs but may require tradeoffs on heavily interactive applications. We focus on real-user metrics rather than synthetic scores.

How do you measure PWA performance?

We use Lighthouse for synthetic testing, Chrome DevTools for profiling, and real user monitoring with web-vitals library for field data. Lab metrics tell us what is possible. Field metrics tell us what users actually experience. We optimize based on field data because that is what affects conversion.

Can you optimize an existing PWA?

Yes. Most existing PWAs have unoptimized caching strategies, oversized bundles, and poor code splitting. We audit the current implementation, identify the highest-impact improvements, and implement them incrementally. Typical improvements are 40 to 60 percent reduction in load time.

How long does PWA performance optimization take?

A performance audit with prioritized recommendations takes 1 week. Implementing caching and bundle optimizations takes 2 to 4 weeks. Ongoing performance monitoring and tuning is typically a monthly retainer. The timeline depends on the number and severity of issues found in the audit.

Make Your PWA Load in Under One Second

Share your PWA URL. We will audit performance, identify the bottlenecks, and implement the optimizations that make every visit faster.