Deploying at the Edge with Cloudflare Workers

Edge Application Architecture

Edge applications invert the traditional deployment model. Instead of centralized servers in one or two regions, your code runs in every Cloudflare data center simultaneously. Requests are routed to the nearest location via Anycast DNS. This architecture excels for latency-sensitive workloads like API gateways, authentication endpoints, content personalization, and server-side rendering. The key constraint is that each execution is stateless — there's no shared memory between requests or locations.

Managing Data at the Edge

The biggest challenge in edge computing is data proximity. Your compute is close to users, but your data might not be. Cloudflare provides several storage primitives optimized for edge access: KV for read-heavy key-value data replicated globally, R2 for object storage, D1 for relational data using SQLite, and Durable Objects for strongly consistent stateful coordination. Choose based on your consistency and latency requirements.

// Read configuration from KV (globally replicated, ~10ms reads)
async function getFeatureFlags(env: Env): Promise<FeatureFlags> {
  const cached = await env.CONFIG_KV.get("feature-flags", "json")
  if (cached) return cached as FeatureFlags

  // Fallback to default flags
  return { darkMode: false, newCheckout: false }
}

// Query user data from D1 (SQLite at the edge)
async function getUserProfile(env: Env, userId: string) {
  const result = await env.DB.prepare(
    "SELECT id, name, email, plan FROM users WHERE id = ?"
  ).bind(userId).first()

  return result
}

Multi-Layer Caching

Effective edge applications use multiple caching layers. The Cloudflare CDN cache handles static assets and cacheable API responses with standard Cache-Control headers. The Workers Cache API provides programmatic control over what gets cached at each edge location, including dynamic content. Workers KV acts as a globally distributed cache for configuration and pre-computed data. Layer these caches based on content freshness requirements and update frequency.

• CDN cache: Static assets with immutable hashes, 1-year TTL
• Cache API: Dynamic responses cached per-location, minutes to hours TTL
• Workers KV: Configuration, feature flags, user settings — seconds to minutes TTL
• No cache: Authentication, real-time data, personalized content

Observability at the Edge

Monitoring edge applications requires different tools than traditional server monitoring. Use Workers Analytics for request volume, error rates, and CPU time metrics. Implement structured logging with wrangler tail for real-time log streaming during development. For production observability, forward logs to an external service (Datadog, Grafana Cloud, or Logflare) using a log-push Worker or Logpush integration. Track edge-specific metrics like cache hit rates, geographic distribution of requests, and per-location latency.