Edge Patterns

Reference for building on edge runtimes — Cloudflare Workers, Vercel Edge, and Deno Deploy.

When to Activate

• Building Cloudflare Workers or Pages Functions
• Writing Vercel Edge Middleware
• Deploying to Deno Deploy
• Debugging "not supported in edge runtime" errors
• Implementing geo-routing, A/B testing, or auth at the edge
• Setting up edge caching strategies
• Migrating a Node.js API route to an edge-compatible runtime to reduce cold-start latency
• Designing stateful edge logic using Durable Objects or Deno KV
• Choosing between Cloudflare, Vercel Edge, and Deno Deploy for a new globally distributed service

Edge Runtime Constraints