Headless CMS and Lighthouse Scores: The Speed Advantage
Headless CMS architectures decouple content from presentation, enabling dramatically faster frontends. Learn how this impacts performance.
Traditional CMS platforms (WordPress, Drupal, AEM) generate HTML on every request, including processing templates, querying databases, and executing plugins. A headless CMS separates content management from content delivery, letting you use fast static frontends.
Headless vs. Traditional Architecture
Traditional CMS
User → Server → Database → Template Engine → HTML → User
(200-2000ms per request)
Headless CMS + Static Frontend
User → CDN → Pre-built HTML → User
(20-50ms per request)
Performance Comparison
We built the same landing page on traditional and headless setups:
| Metric | WordPress (traditional) | Contentful + Next.js (headless) |
|---|---|---|
| TTFB | 400-800ms | 20-50ms |
| LCP | 2.5-4.0s | 1.0-1.5s |
| CLS | 0.05-0.15 | 0.01-0.03 |
| TBT | 500-1200ms | 100-300ms |
| Lighthouse | 45-70 | 85-98 |
| Page weight | 1-3MB | 200-500KB |
Popular Headless CMS Options
| CMS | Type | Best For | Free Tier |
|---|---|---|---|
| Contentful | API-based | Enterprise, complex content models | 25K records |
| Sanity | API-based | Real-time collaboration | Generous |
| Strapi | Self-hosted | Full control, open source | Unlimited |
| Payload CMS | Self-hosted | TypeScript-native, modern | Unlimited |
| Ghost | Self-hosted | Blogging, newsletters | Self-host free |
| Hygraph | API-based | GraphQL-native | 25K records |
| Keystatic | Git-based | Markdown/YAML content | Free |
Frontend Frameworks for Headless
Static Site Generation (Fastest)
| Framework | JS Shipped | Build Speed | Best For |
|---|---|---|---|
| Astro | 0KB (default) | Fast | Content sites, blogs |
| 11ty (Eleventy) | 0KB (default) | Very fast | Simple sites |
| Hugo | 0KB | Fastest | Large content sites |
| Next.js (SSG) | ~50KB | Moderate | Complex apps + content |
Server-Side Rendering (Dynamic)
| Framework | JS Shipped | Best For |
|---|---|---|
| Next.js (SSR) | ~50KB | Dynamic content, personalization |
| SvelteKit | ~30KB | Interactive sites |
| Nuxt.js | ~50KB | Vue ecosystem |
The Performance Wins
1. CDN-First Delivery
Pre-built pages served from CDN edge locations worldwide. TTFB drops from 200-800ms to 20-50ms.
2. No Runtime Database
Static pages don't query databases on each request. No database = no database bottleneck.
3. Minimal JavaScript
Content pages don't need JavaScript to render. Astro and 11ty ship 0KB of JS by default.
4. Better Caching
Static files have perfect cache headers: Cache-Control: public, max-age=31536000, immutable.
5. Security
No server-side code running per request = smaller attack surface. No SQL injection, no plugin vulnerabilities.
When NOT to Go Headless
- Small teams without developers (traditional CMS is easier)
- Sites that need WYSIWYG visual editing (some headless CMS have preview, but it's not the same)
- E-commerce with complex real-time features (headless commerce is possible but harder)
- Rapid prototyping (traditional CMS is faster to launch)
Migration Strategy
- Start with a new section — build your blog or marketing pages headless while keeping the main site traditional
- Validate performance — measure the headless section vs. traditional
- Gradually migrate — move sections one at a time
- Monitor continuously — ensure performance holds as content grows
Monitor Your Headless Performance
Even pre-built static pages can degrade when content grows or third-party scripts are added. BadPageSpeed monitors your performance continuously.
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