Cloudflare Workers
V8-isolate serverless functions running at the edge in 300+ Cloudflare PoPs worldwide. Near-zero cold starts (< 5ms), global low latency, and a rich ecosystem including KV, R2, Durable Objects, and Queues.
Why Cloudflare Workers?
Global low-latency API endpoints where cold start time matters
Edge middleware (auth, redirects, A/B testing) without hitting your origin
Replacing traditional serverless with a faster, cheaper alternative
Signal Breakdown
What drives the Trust Score
Download Trend
Last 12 months
Tradeoffs & Caveats
Know before you commitNeed Node.js-compatible APIs not available in the Workers runtime (some npm packages won't work)
Long-running tasks > 30 seconds — Workers CPU time limit applies
Complex stateful workloads — Durable Objects have a learning curve; use a traditional server
Pricing
Free tier & paid plans
100k requests/day · 10ms CPU/request
$5/mo Workers Paid (10M requests)
Extremely generous free tier; paid plan extends CPU time to 30s
Alternative Tools
Other options worth considering
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Often Used Together
Complementary tools that pair well with Cloudflare Workers
Learning Resources
Docs, videos, tutorials, and courses
Get Started
Repository and installation options
View on GitHub
github.com/cloudflare/workers-sdk
npm install -g wranglernpm create cloudflare@latestQuick Start
Copy and adapt to get going fast
// wrangler.toml
// name = "my-worker"
// main = "src/index.ts"
// compatibility_date = "2024-01-01"
export interface Env {
CACHE: KVNamespace;
API_SECRET: string;
}
export default {
async fetch(req: Request, env: Env): Promise<Response> {
const cacheKey = new URL(req.url).pathname;
// Try KV cache first
const cached = await env.CACHE.get(cacheKey);
if (cached) return new Response(cached, { headers: { 'x-cache': 'HIT' } });
// Fetch from origin
const data = await fetch('https://api.example.com' + cacheKey).then(r => r.text());
await env.CACHE.put(cacheKey, data, { expirationTtl: 60 });
return new Response(data, { headers: { 'x-cache': 'MISS' } });
},
};Code Examples
Common usage patterns
Edge authentication middleware
Validate JWT tokens at the edge before hitting your origin
import { jwtVerify, importSPKI } from 'jose';
export interface Env { JWT_PUBLIC_KEY: string; }
export default {
async fetch(req: Request, env: Env): Promise<Response> {
const token = req.headers.get('Authorization')?.replace('Bearer ', '');
if (!token) {
return Response.json({ error: 'Unauthorized' }, { status: 401 });
}
try {
const publicKey = await importSPKI(env.JWT_PUBLIC_KEY, 'RS256');
const { payload } = await jwtVerify(token, publicKey);
// Forward to origin with user info in header
const req2 = new Request(req);
req2.headers.set('x-user-id', payload.sub as string);
return fetch(req2);
} catch {
return Response.json({ error: 'Invalid token' }, { status: 403 });
}
},
};KV-backed feature flags
Read feature flags from KV with sub-millisecond latency
export interface Env { FLAGS: KVNamespace; }
export default {
async fetch(req: Request, env: Env): Promise<Response> {
const url = new URL(req.url);
const userId = url.searchParams.get('userId') ?? 'anonymous';
// Read flag from KV — data replicated to every edge node
const rawFlags = await env.FLAGS.get('feature_flags', 'json') as Record<string, boolean> | null;
const flags = rawFlags ?? {};
const isNewUI = flags['new_dashboard'] ?? false;
return Response.json({
userId,
flags: { newDashboard: isNewUI },
});
},
};Community Notes
Real experiences from developers who've used this tool