Performance standards

Performance model

• Static Astro output is the baseline performance strategy.
• Edge workers and headers layer on caching and optimization behavior.

Image strategy

• Source images live under src/assets/images.
• Optimized delivery is supported by the image worker route set (wrangler.image.toml) and image-optimizer.js.
• Image resize path expects supported extension plus a width query parameter.

Cache-header standards

public/_headers is the deploy-critical source of cache and security headers.

Expected classes:

• /assets/*: long-lived immutable cache.
• Image extensions (*.jpg, *.png, *.webp, etc.): medium-lived cache with stale-while-revalidate.
• /api/*: no-store/no-cache headers with CORS declarations.

Validation tools

Workspace scripts:

• yarn workspace cosmos-digital-services test:performance
• yarn workspace cosmos-digital-services test:web-vitals

Caveats

• Performance scripts include assumptions and placeholder endpoints (for example /api/test checks in tests/performance.test.mjs) and may not represent every production route.
• test:web-vitals uses Puppeteer + Vitest-style APIs; validate local prerequisites before treating failures as regressions.
• Use these scripts as guardrails, then confirm with real browser/network profiling for major launches.