Edge rendering means generating the HTML of your page at a CDN edge node, physically close to the user, instead of at a single origin server in one region. Cloudflare Workers, Vercel Edge Functions, and Deno Deploy are all edge platforms.
Why it matters
Latency is half the perceived performance of a website. A page rendered 50ms from the user feels significantly faster than one rendered 250ms away, even if the page itself is identical. For global audiences, edge rendering is the difference between snappy and sluggish.
Common mistakes
- Edge-rendering everything. If your page depends on a database call to a single region, rendering at the edge just means the bottleneck moves. Prefer SSG when you can; edge-render only when you need per-request logic.
- Forgetting the cold start. Edge runtimes have constraints (no full Node.js, smaller memory limits) that can surprise you when you port a server-side page over.
- Ignoring the cost model. Edge functions are usually billed per invocation; for a busy SaaS, this can exceed origin-server costs if every page is dynamic.