WEB DEVELOPMENT
SaaS Platform Rebuild: Astro + Preact Islands Performance
Complete platform rebuild using Astro + Preact Islands, taking mobile LCP from 6.2s to 0.4s.
98
Lighthouse
0.4s
LCP
The Challenge
A SaaS dashboard arrived as a monolithic React app that took 6.2 seconds to load on mobile. Lighthouse was 34. It needed a complete rethink, not a patch.
Our Approach
Architecture
We migrated from a single-page React application to Astro with Preact Islands. Content pages became static HTML (zero JavaScript). Interactive dashboards became isolated Preact components that load only when needed.
Performance Engineering
- Font optimization: Subset Inter to Latin characters only, preload critical fonts
- Image pipeline: Automatic WebP conversion, responsive srcsets, lazy loading
- Code splitting: Every page ships only the JavaScript it needs
- Edge deployment: Content served from 200+ edge locations globally
AI Search Optimization
- Added
llms.txtwith structured business information - Implemented
LocalBusinessandSoftwareApplicationschema - Configured
robots.txtto allow AI crawlers - Created citation-friendly content structure
Results
| Metric | Before | After | Change |
|---|---|---|---|
| Lighthouse | 34 | 98 | +64 points |
| LCP | 6.2s | 0.4s | -93% |
| CLS | 0.22 | 0.01 | -95% |
| TBT | 1,200ms | 42ms | -97% |
Faster pages are only half the job — the same build ships llms.txt, structured schema and crawlable content so the product can also surface in AI answers.
Related reading:
- Our Web Development Service — Lighthouse 95+ targets
- How We Engineer Sub-Second Lighthouse Scores — Our technical blueprint
- What is GEO? — Why AI search matters for SaaS