How We Helped a SaaS Company Improve Their Score by 40 Points

A B2B SaaS company in the project management space came to us with a problem: their marketing site had a Lighthouse mobile score of 35, a bounce rate of 65%, and their trial signup conversion rate was declining. Here's what we found and fixed.

The Starting Point

Initial Audit Results

Metric	Score	Status
Lighthouse Mobile	35	🔴 Poor
LCP	5.8s	🔴 Poor
FID/INP	380ms	🔴 Poor
CLS	0.32	🔴 Poor
TBT	1,200ms	🔴 Poor
Page Weight	4.2MB	🔴 Heavy
HTTP Requests	87	🔴 Excessive

Root Causes Identified

1. Hero video autoplaying on mobile — 2.8MB video file loading on cellular connections
2. 12 third-party scripts — analytics, chat, heatmaps, A/B testing, personalization, retargeting
3. Unoptimized images — PNG screenshots at 3000px wide, no lazy loading
4. Three animation libraries — GSAP, AOS, and CSS animations all used on the same page
5. No caching headers — every asset re-downloaded on repeat visits
6. Custom fonts — 6 weights of Inter loaded (300KB+ of font files)

Phase 1: Quick Wins (Week 1)

Image Optimization

• Converted PNGs to WebP with AVIF fallback
• Resized images to 2x display size (not 4-5x)
• Added loading="lazy" to all below-fold images
• Added explicit width and height attributes

Impact: -1.8MB page weight, CLS improved from 0.32 to 0.04

Font Optimization

• Reduced font weights from 6 to 3 (400, 500, 700)
• Added font-display: swap
• Self-hosted fonts instead of Google Fonts API
• Preloaded the primary weight

Impact: -200KB, LCP improved by 400ms

Results After Week 1

Metric	Before	After Week 1
Lighthouse	35	52
Page Weight	4.2MB	1.8MB
LCP	5.8s	3.2s
CLS	0.32	0.04

Phase 2: Third-Party Script Audit (Week 2)

We audited all 12 third-party scripts:

Script	Size	Decision
Google Analytics (GA4)	45KB	✅ Keep
Hotjar	85KB	❌ Remove (not being used)
Intercom	300KB	⚠️ Load on scroll
Drift (chat)	250KB	❌ Remove (duplicate of Intercom)
Segment	70KB	❌ Remove (GA4 sufficient)
Facebook Pixel	60KB	✅ Keep (defer)
Google Tag Manager	80KB	⚠️ Simplify tags
Optimizely	150KB	❌ Remove (no active tests)
Clearbit	90KB	❌ Remove
HubSpot tracking	95KB	✅ Keep (CRM integration)
Stripe.js	40KB	✅ Keep (load on pricing page only)
Sentry	30KB	✅ Keep

Removed 5 scripts, deferred 2, conditionally loaded 1.

Impact: -655KB JavaScript, TBT dropped from 1,200ms to 450ms

Phase 3: Architecture Changes (Weeks 3-4)

Replaced Hero Video with Static Image

• Desktop: optimized WebP hero image (80KB vs. 2.8MB video)
• Added video as optional "Watch Demo" click-to-play
• LCP element now loads in 800ms instead of 4.5s

Consolidated Animation Library

• Replaced GSAP + AOS with CSS animations only
• Used @media (prefers-reduced-motion) for accessibility
• Animations trigger on IntersectionObserver (no library needed)

Added Proper Caching

Cache-Control: public, max-age=31536000, immutable  (static assets)
Cache-Control: public, max-age=3600, s-maxage=86400 (HTML pages)

Final Results

Metric	Before	After	Improvement
Lighthouse Mobile	35	78	+43 points
LCP	5.8s	1.4s	-76%
INP	380ms	120ms	-68%
CLS	0.32	0.02	-94%
TBT	1,200ms	180ms	-85%
Page Weight	4.2MB	620KB	-85%
HTTP Requests	87	24	-72%

Business Impact (30 Days Post-Optimization)

• Bounce rate: 65% → 48% (-26%)
• Trial signups: +22% increase
• Pages per session: 2.1 → 3.4 (+62%)
• Organic traffic: +15% (improved rankings)

Key Takeaways

1. Images and video are usually the biggest win — optimize them first
2. Third-party scripts accumulate over time — audit quarterly
3. You don't need most analytics tools — GA4 alone is often sufficient
4. CSS animations are almost always enough — you rarely need GSAP on a marketing site
5. Caching is free performance — set proper headers

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