Astro 5 vs SvelteKit 2
Real-world performance comparison based on identical SaaS dashboard implementations.
Astro 5
VPS
The web framework for content-driven websites. Astro's revolutionary Islands architecture ships zero JavaScript by default—interactive components hydrate independently only where needed, dramatically reducing bundle sizes. Astro 5 introduces Content Layer for type-safe content collections, Server Islands for mixing static and dynamic content, and improved build performance. The framework is UI-agnostic: use React, Vue, Svelte, Solid, or vanilla JS components in the same project. Perfect for marketing sites, documentation, blogs, and any content-heavy application where performance matters. Astro consistently achieves perfect Lighthouse scores with minimal effort.
SvelteKit 2
VPS
The official Svelte application framework, combining Svelte's compile-time magic with a powerful routing and rendering system. SvelteKit compiles your components to surgical DOM updates with no virtual DOM overhead. Features file-based routing with layouts, server-side rendering, static prerendering, and streaming. Load functions provide type-safe data loading with automatic request deduplication. Form actions handle progressive enhancement elegantly. SvelteKit apps are remarkably small—the compiler eliminates unused code and the runtime is minimal. Ideal for developers who want React-like DX with significantly better performance characteristics.
Performance Metrics
Lower is better for all metrics. Green indicates the faster framework.
| Metric | Astro 5 | SvelteKit 2 | Winner |
|---|---|---|---|
| TTFB (p50) | 50.5ms | 44.55ms | ▶ |
| TTFB (p95) | 52.23ms | 48.19ms | ▶ |
| LCP (p50) | 80ms | 82ms | ◀ |
| LCP (p95) | 86.2ms | 95ms | ◀ |
| CLS | 0 | 0 | = |
| TBT | 0 ms | 0 ms | = |
| LCP → TTFB | 214 ms | 175 ms | ▶ |
| LCP → Load Delay | 0 ms | 0 ms | = |
| LCP → Load Duration | 0 ms | 0 ms | = |
| LCP → Render Delay | 535 ms | 523 ms | ▶ |
| Performance Score | 99 | 98 | ◀ |
| SEO Score | 92 | 83 | ◀ |
| Accessibility Score | 79 | 86 | ▶ |
| Best Practices Score | 100 | 100 | = |
LLM Understanding (Claude Opus 4.5)
How efficiently Claude Opus 4.5 understands the codebase. Based on exploration + validation tests.
| Metric | Astro 5 | SvelteKit 2 | Winner |
|---|---|---|---|
| Exploration Time | 3955ms | 4268ms | ◀ |
| Exploration Tokens | 2756 | 4454 | ◀ |
| Files Examined | 8 | 12 | ◀ |
| Validation Accuracy | 86% | 91% | ▶ |
| Time Per File | 494ms | 356ms | ▶ |
| Tokens Per File | 3496 | 3019 | ▶ |
| Efficiency Score | 33.49 | 28.51 | ◀ |
LLM Understanding (Claude Haiku 4.5)
How efficiently Claude Haiku 4.5 understands the codebase. Based on exploration + validation tests.
| Metric | Astro 5 | SvelteKit 2 | Winner |
|---|---|---|---|
| Exploration Time | 2240ms | 2252ms | ◀ |
| Exploration Tokens | 2764 | 4502 | ◀ |
| Files Examined | 8 | 12 | ◀ |
| Validation Accuracy | 81% | 82% | ▶ |
| Time Per File | 280ms | 188ms | ▶ |
| Tokens Per File | 3474 | 3010 | ▶ |
| Efficiency Score | 49.18 | 37.63 | ◀ |
Build Metrics
| Metric | Astro 5 | SvelteKit 2 | Winner |
|---|---|---|---|
| Bundle Size (JS) | 242.7KB | 176.2KB | ▶ |
| Bundle Size (CSS) | 22.6KB | 23.6KB | ◀ |
| Build Time | 0s | 0s | = |
| Dependencies | 18 | 19 | ◀ |
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