Vercel Edge Best Practices (2025)

Edge is about latency discipline. These are the patterns that consistently work.

What to Run at the Edge

• Simple auth checks, A/B flags, geolocation routing.
• Caching API responses close to the user.
• Lightweight personalization assembled from cookies/headers.

Cache Strategy

• Prefer stale-while-revalidate for dynamic lists.
• Tag your cache keys; purge by tag on writes.
• Generate small, shareable JSON—avoid megabyte payloads.

Images

• Use next/image with sizes; preconnect your CDN domains.
• Convert large hero images to 1200×630 webp/avif.

Observability

• Emit latency metrics and cache hit rate per route.
• Log edge errors separately from server logs.

Fast apps are simple apps. Keep the edge logic thin and measurable.