Astro 5 vs SvelteKit 2

Real-world performance comparison based on identical SaaS dashboard implementations.

Astro 5

Astro 5

VPS

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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

SvelteKit 2

VPS

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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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