edge-computing-patterns_skill

Overview

This skill teaches patterns for deploying TypeScript applications to edge runtimes like Cloudflare Workers, Vercel Edge Functions, and Deno Deploy. It focuses on reducing latency, handling runtime constraints, and using edge primitives such as caching, durable state, and middleware. You will learn practical approaches for authentication, rate limiting, streaming, and geo-routing at the edge.

How this skill works

The skill inspects common edge runtime capabilities and limitations, then provides concrete code patterns and configurations for each platform. It demonstrates using fetch, Request/Response, caches, KV/Durable Objects, and edge middleware to run logic close to users. Examples include caching strategies, stateful counters, authentication middleware, and A/B testing via edge rewrites.

When to use it

• When you need global, low-latency responses (<50ms) for user-facing services
• To perform authentication, authorization, or request validation before hitting origin
• For A/B testing, feature flags, geo-routing, and localization at the edge
• To implement rate limiting or lightweight DDoS mitigation near the client
• When transforming responses (image optimization, HTML rewriting, streaming)

Best practices

• Keep bundles small (<1MB) and prefer native Web APIs over large npm packages
• Use upstream edge caching and streaming for large responses to reduce origin load
• Store ephemeral counters and global state with Durable Objects or KV depending on consistency needs
• Handle runtime constraints explicitly: avoid Node-native APIs and test cold/warm starts
• Secure secrets with environment variables and validate tokens at the edge
• Monitor latency, error rates, and cold start behavior across regions

Example use cases

• Global API gateway that validates JWTs at the edge and forwards requests to regional origins
• A/B testing middleware that assigns buckets and rewrites requests for experiments
• Edge image optimizer that streams transformed images and caches results globally
• Rate limiter using KV with short TTLs to protect backend services
• Geo-routing service that serves localized content and sets region headers