Edge Computing for Frontend Developers: Complete Guide 2026

Edge computing has transformed from an infrastructure concern into a critical frontend development skill. In 2026, the line between frontend and backend continues to blur as developers deploy code that runs milliseconds away from users worldwide. This comprehensive guide covers everything frontend developers need to know about edge computing—from fundamental concepts to production-ready implementations.

Whether you’re optimizing an existing application or architecting a new system, understanding edge computing is essential for building modern, performant web applications.

What Is Edge Computing for Frontend Developers?

Edge computing brings computation and data storage closer to the sources of data. For frontend developers, this means running server-side logic on distributed servers located near users, rather than in centralized data centers.

Traditional Architecture vs. Edge Architecture

Traditional Architecture:

User in Tokyo → CDN (static files) → Origin Server in Virginia → Database
                                   ↓
                              500ms+ latency

Edge Architecture:

User in Tokyo → Edge Server in Tokyo → Origin (if needed)
                    ↓
               50ms latency
               (Dynamic content rendered at edge)

Why Frontend Developers Need Edge Skills

The web platform evolution has fundamentally changed what “frontend” means:

1. Server Components: React Server Components, Astro, and similar technologies blur the client-server boundary
2. Edge Rendering: SSR and SSG at the edge for personalized, dynamic content
3. API Routes: Frontend frameworks now include backend capabilities
4. Real-time Features: Edge-native solutions for WebSockets and streaming

---

Edge Platforms: A Frontend Developer’s Guide

Multiple platforms offer edge computing capabilities. Understanding their strengths helps you choose the right tool.

Vercel Edge Functions

Vercel Edge Functions run on Vercel’s Edge Network, powered by V8 isolates. They’re ideal for Next.js applications.

Key Features:

• Sub-millisecond cold starts
• Streaming responses
• Global deployment by default
• Native Next.js integration

Basic Edge Function:

// app/api/hello/route.ts
export const runtime = 'edge';

export async function GET(request: Request) {
  const { searchParams } = new URL(request.url);
  const name = searchParams.get('name') || 'World';

  return new Response(`Hello, ${name}!`, {
    headers: {
      'content-type': 'text/plain',
    },
  });
}

Edge Middleware:

// middleware.ts
import { NextResponse } from 'next/server';
import type { NextRequest } from 'next/server';

export function middleware(request: NextRequest) {
  // Get user's country from edge
  const country = request.geo?.country || 'US';

  // Personalize based on location
  const response = NextResponse.next();
  response.headers.set('x-user-country', country);

  // A/B testing at the edge
  const bucket = Math.random() < 0.5 ? 'control' : 'experiment';
  response.cookies.set('ab-bucket', bucket);

  return response;
}

export const config = {
  matcher: ['/((?!_next/static|favicon.ico).*)'],
};

Cloudflare Workers

Cloudflare Workers provide the most mature edge computing platform with extensive APIs.

Key Features:

• 200+ edge locations worldwide
• KV storage for edge data
• Durable Objects for stateful applications
• Workers AI for edge machine learning

Basic Worker:

// src/index.js
export default {
  async fetch(request, env, ctx) {
    const url = new URL(request.url);

    if (url.pathname === '/api/data') {
      // Fetch from KV store at the edge
      const cachedData = await env.MY_KV.get('data-key', 'json');

      if (cachedData) {
        return Response.json(cachedData);
      }

      // Fetch from origin and cache
      const response = await fetch('https://api.origin.com/data');
      const data = await response.json();

      // Cache for 1 hour
      ctx.waitUntil(env.MY_KV.put('data-key', JSON.stringify(data), {
        expirationTtl: 3600
      }));

      return Response.json(data);
    }

    return new Response('Not Found', { status: 404 });
  }
};

Wrangler Configuration:

# wrangler.toml
name = "my-edge-app"
main = "src/index.js"
compatibility_date = "2026-01-01"

[[kv_namespaces]]
binding = "MY_KV"
id = "abc123"

[vars]
ENVIRONMENT = "production"

Deno Deploy

Deno Deploy offers edge computing with first-class TypeScript support and Web Standard APIs.

Key Features:

• TypeScript out of the box
• Web-standard APIs
• Built-in KV database
• GitHub integration

Deno Edge Function:

// main.ts
import { serve } from "https://deno.land/[email protected]/http/server.ts";

const kv = await Deno.openKv();

serve(async (request: Request) => {
  const url = new URL(request.url);

  if (url.pathname === "/api/counter") {
    // Atomic increment at the edge
    const key = ["counters", "visits"];
    const result = await kv.atomic()
      .sum(key, 1n)
      .commit();

    const entry = await kv.get(key);

    return Response.json({
      count: entry.value?.toString() || "0"
    });
  }

  return new Response("Hello from the Edge!");
}, { port: 8000 });

AWS CloudFront Functions & Lambda@Edge

AWS offers two edge computing options with different capabilities.

CloudFront Functions (lightweight):

function handler(event) {
  var request = event.request;
  var headers = request.headers;

  // Add security headers at the edge
  var response = {
    statusCode: 200,
    statusDescription: 'OK',
    headers: {
      'strict-transport-security': { value: 'max-age=31536000' },
      'content-security-policy': { value: "default-src 'self'" },
      'x-content-type-options': { value: 'nosniff' },
      'x-frame-options': { value: 'DENY' }
    }
  };

  return response;
}

Lambda@Edge (full compute):

exports.handler = async (event) => {
  const request = event.Records[0].cf.request;

  // Personalization at the edge
  const userAgent = request.headers['user-agent'][0].value;
  const isMobile = /Mobile|Android/.test(userAgent);

  if (isMobile) {
    request.uri = request.uri.replace(/\.html$/, '.mobile.html');
  }

  return request;
};

---

Common Edge Computing Patterns

Frontend developers frequently implement these patterns at the edge.

Pattern 1: Personalization at the Edge

Deliver personalized content without origin round-trips:

// Vercel Edge Middleware for personalization
import { NextResponse } from 'next/server';
import type { NextRequest } from 'next/server';

export async function middleware(request: NextRequest) {
  const response = NextResponse.next();

  // Get personalization context
  const country = request.geo?.country || 'US';
  const city = request.geo?.city || 'Unknown';
  const userAgent = request.headers.get('user-agent') || '';

  // Determine content variant
  const isMobile = /Mobile|Android|iPhone/.test(userAgent);
  const locale = getPreferredLocale(request.headers.get('accept-language'));
  const currency = getCurrencyForCountry(country);

  // Set headers for downstream use
  response.headers.set('x-personalization', JSON.stringify({
    country,
    city,
    isMobile,
    locale,
    currency
  }));

  // Rewrite to personalized content
  if (request.nextUrl.pathname === '/') {
    return NextResponse.rewrite(
      new URL(`/${locale}/home?currency=${currency}`, request.url),
      { headers: response.headers }
    );
  }

  return response;
}

function getPreferredLocale(acceptLanguage: string | null): string {
  if (!acceptLanguage) return 'en';

  const locales = ['en', 'ja', 'de', 'fr', 'es', 'zh'];
  const preferred = acceptLanguage.split(',')[0].split('-')[0];

  return locales.includes(preferred) ? preferred : 'en';
}

function getCurrencyForCountry(country: string): string {
  const currencyMap: Record<string, string> = {
    US: 'USD',
    JP: 'JPY',
    GB: 'GBP',
    DE: 'EUR',
    MY: 'MYR'
  };

  return currencyMap[country] || 'USD';
}

Pattern 2: A/B Testing at the Edge

Implement consistent A/B testing without client-side flicker:

// Cloudflare Worker for A/B testing
interface Env {
  EXPERIMENTS_KV: KVNamespace;
}

export default {
  async fetch(request: Request, env: Env): Promise<Response> {
    const url = new URL(request.url);

    // Get or assign experiment bucket
    const cookies = parseCookies(request.headers.get('cookie'));
    let bucket = cookies['ab-experiment'];

    if (!bucket) {
      // Assign new user to experiment
      const experiment = await env.EXPERIMENTS_KV.get('homepage-v2', 'json') as {
        variants: { id: string; weight: number }[];
      };

      bucket = assignVariant(experiment.variants);
    }

    // Rewrite to experiment variant
    if (url.pathname === '/') {
      const variantUrl = new URL(url);
      variantUrl.pathname = `/experiments/${bucket}/index.html`;

      const response = await fetch(variantUrl);
      const modifiedResponse = new Response(response.body, response);

      // Set cookie for consistent experience
      modifiedResponse.headers.append(
        'Set-Cookie',
        `ab-experiment=${bucket}; Path=/; Max-Age=2592000; SameSite=Lax`
      );

      // Track assignment for analytics
      await trackExperimentAssignment(bucket, request);

      return modifiedResponse;
    }

    return fetch(request);
  }
};

function assignVariant(variants: { id: string; weight: number }[]): string {
  const random = Math.random();
  let cumulative = 0;

  for (const variant of variants) {
    cumulative += variant.weight;
    if (random < cumulative) {
      return variant.id;
    }
  }

  return variants[0].id;
}

Pattern 3: Edge-Side Includes (ESI)

Compose pages from cached fragments at the edge:

// Edge function for ESI-style composition
export async function onRequest(context: EventContext) {
  const url = new URL(context.request.url);

  if (url.pathname.startsWith('/product/')) {
    // Fetch page components in parallel
    const [header, productContent, recommendations, footer] = await Promise.all([
      fetchCachedFragment('/fragments/header'),
      fetchProductContent(url.pathname),
      fetchPersonalizedRecommendations(context.request),
      fetchCachedFragment('/fragments/footer')
    ]);

    // Compose final HTML
    const html = `
      <!DOCTYPE html>
      <html>
        <head>
          <title>${productContent.title}</title>
        </head>
        <body>
          ${header}
          <main>${productContent.html}</main>
          <aside>${recommendations}</aside>
          ${footer}
        </body>
      </html>
    `;

    return new Response(html, {
      headers: {
        'content-type': 'text/html',
        'cache-control': 'public, max-age=60, stale-while-revalidate=300'
      }
    });
  }

  return context.next();
}

async function fetchCachedFragment(path: string): Promise<string> {
  // Fragments cached at edge for 1 hour
  const response = await fetch(`https://origin.com${path}`, {
    cf: { cacheTtl: 3600 }
  });
  return response.text();
}

async function fetchPersonalizedRecommendations(request: Request): Promise<string> {
  // Personalized content based on cookies/geo
  const userId = getCookie(request, 'user_id');
  const country = request.cf?.country || 'US';

  const response = await fetch(
    `https://api.origin.com/recommendations?user=${userId}&country=${country}`
  );
  const data = await response.json();

  return renderRecommendations(data);
}

Pattern 4: Edge Authentication

Validate authentication at the edge before requests reach origin:

// JWT validation at the edge
import { jwtVerify } from 'jose';

interface Env {
  JWT_SECRET: string;
}

export default {
  async fetch(request: Request, env: Env): Promise<Response> {
    const url = new URL(request.url);

    // Skip auth for public routes
    if (isPublicRoute(url.pathname)) {
      return fetch(request);
    }

    // Extract and validate JWT
    const authHeader = request.headers.get('authorization');

    if (!authHeader?.startsWith('Bearer ')) {
      return new Response('Unauthorized', { status: 401 });
    }

    const token = authHeader.slice(7);

    try {
      const secret = new TextEncoder().encode(env.JWT_SECRET);
      const { payload } = await jwtVerify(token, secret);

      // Add user context to request
      const modifiedHeaders = new Headers(request.headers);
      modifiedHeaders.set('x-user-id', payload.sub as string);
      modifiedHeaders.set('x-user-role', payload.role as string);

      const modifiedRequest = new Request(request, {
        headers: modifiedHeaders
      });

      return fetch(modifiedRequest);
    } catch (error) {
      return new Response('Invalid token', { status: 401 });
    }
  }
};

function isPublicRoute(pathname: string): boolean {
  const publicRoutes = ['/login', '/register', '/api/health', '/public'];
  return publicRoutes.some(route => pathname.startsWith(route));
}

Pattern 5: Smart Caching with Stale-While-Revalidate

Implement intelligent caching strategies at the edge:

// Cloudflare Worker with smart caching
interface Env {
  CACHE_KV: KVNamespace;
}

export default {
  async fetch(request: Request, env: Env, ctx: ExecutionContext): Promise<Response> {
    const cacheKey = new URL(request.url).pathname;

    // Try to get from edge cache
    const cached = await env.CACHE_KV.getWithMetadata(cacheKey, 'json');

    if (cached.value) {
      const metadata = cached.metadata as { expires: number; stale: number };
      const now = Date.now();

      if (now < metadata.expires) {
        // Fresh cache hit
        return Response.json(cached.value, {
          headers: { 'x-cache': 'HIT' }
        });
      }

      if (now < metadata.stale) {
        // Stale-while-revalidate
        ctx.waitUntil(revalidateCache(request, env, cacheKey));

        return Response.json(cached.value, {
          headers: { 'x-cache': 'STALE' }
        });
      }
    }

    // Cache miss - fetch from origin
    return revalidateCache(request, env, cacheKey);
  }
};

async function revalidateCache(
  request: Request,
  env: Env,
  cacheKey: string
): Promise<Response> {
  const response = await fetch(`https://api.origin.com${cacheKey}`);
  const data = await response.json();

  // Store with TTL metadata
  const now = Date.now();
  await env.CACHE_KV.put(cacheKey, JSON.stringify(data), {
    metadata: {
      expires: now + 60000,      // Fresh for 1 minute
      stale: now + 300000        // Stale for 5 minutes
    }
  });

  return Response.json(data, {
    headers: { 'x-cache': 'MISS' }
  });
}

---

Edge Data Storage

Edge computing requires edge-native data storage solutions.

Cloudflare KV

Key-value storage optimized for read-heavy workloads:

// KV operations at the edge
interface Env {
  USER_PREFERENCES: KVNamespace;
}

export default {
  async fetch(request: Request, env: Env): Promise<Response> {
    const url = new URL(request.url);
    const userId = url.searchParams.get('userId');

    if (request.method === 'GET') {
      // Read user preferences
      const prefs = await env.USER_PREFERENCES.get(`user:${userId}`, 'json');
      return Response.json(prefs || { theme: 'light', language: 'en' });
    }

    if (request.method === 'POST') {
      // Update preferences
      const body = await request.json();

      await env.USER_PREFERENCES.put(`user:${userId}`, JSON.stringify(body), {
        expirationTtl: 86400 * 30  // 30 days
      });

      return Response.json({ success: true });
    }

    return new Response('Method not allowed', { status: 405 });
  }
};

Cloudflare Durable Objects

Stateful compute at the edge for real-time applications:

// Durable Object for real-time collaboration
export class DocumentRoom {
  state: DurableObjectState;
  sessions: Map<WebSocket, { userId: string }>;
  document: string;

  constructor(state: DurableObjectState) {
    this.state = state;
    this.sessions = new Map();
    this.document = '';
  }

  async fetch(request: Request): Promise<Response> {
    const url = new URL(request.url);

    if (url.pathname === '/websocket') {
      // Handle WebSocket upgrade
      const pair = new WebSocketPair();
      const [client, server] = Object.values(pair);

      const userId = url.searchParams.get('userId') || 'anonymous';
      this.handleSession(server, userId);

      return new Response(null, { status: 101, webSocket: client });
    }

    return new Response('Not found', { status: 404 });
  }

  handleSession(webSocket: WebSocket, userId: string) {
    webSocket.accept();
    this.sessions.set(webSocket, { userId });

    // Send current document state
    webSocket.send(JSON.stringify({
      type: 'sync',
      document: this.document,
      users: Array.from(this.sessions.values()).map(s => s.userId)
    }));

    webSocket.addEventListener('message', (event) => {
      const message = JSON.parse(event.data as string);

      if (message.type === 'edit') {
        // Apply edit and broadcast
        this.document = applyEdit(this.document, message.edit);

        this.broadcast({
          type: 'edit',
          userId,
          edit: message.edit
        }, webSocket);
      }
    });

    webSocket.addEventListener('close', () => {
      this.sessions.delete(webSocket);
      this.broadcast({ type: 'user_left', userId });
    });
  }

  broadcast(message: object, exclude?: WebSocket) {
    const json = JSON.stringify(message);

    for (const [ws] of this.sessions) {
      if (ws !== exclude) {
        ws.send(json);
      }
    }
  }
}

Deno KV

Built-in key-value database for Deno Deploy:

// Deno KV for edge data
const kv = await Deno.openKv();

// Atomic transactions
async function transferBalance(fromId: string, toId: string, amount: number) {
  const fromKey = ["balances", fromId];
  const toKey = ["balances", toId];

  // Atomic check-and-update
  let success = false;

  while (!success) {
    const fromEntry = await kv.get<number>(fromKey);
    const toEntry = await kv.get<number>(toKey);

    const fromBalance = fromEntry.value || 0;
    const toBalance = toEntry.value || 0;

    if (fromBalance < amount) {
      throw new Error("Insufficient balance");
    }

    const result = await kv.atomic()
      .check(fromEntry)
      .check(toEntry)
      .set(fromKey, fromBalance - amount)
      .set(toKey, toBalance + amount)
      .commit();

    success = result.ok;
  }

  return { success: true };
}

// Secondary indexes
async function addUser(user: { id: string; email: string; name: string }) {
  await kv.atomic()
    .set(["users", user.id], user)
    .set(["users_by_email", user.email], user.id)
    .commit();
}

async function getUserByEmail(email: string) {
  const idEntry = await kv.get<string>(["users_by_email", email]);
  if (!idEntry.value) return null;

  const userEntry = await kv.get(["users", idEntry.value]);
  return userEntry.value;
}

---

Performance Optimization at the Edge

Maximize edge computing benefits with these optimization techniques.

Streaming Responses

Stream content as it’s generated:

// Streaming response from edge
export async function onRequest(context: EventContext): Promise<Response> {
  const { readable, writable } = new TransformStream();
  const writer = writable.getWriter();
  const encoder = new TextEncoder();

  // Start streaming immediately
  context.waitUntil((async () => {
    // Write HTML head immediately
    await writer.write(encoder.encode(`
      <!DOCTYPE html>
      <html>
        <head><title>Streaming Page</title></head>
        <body>
          <header>Loading content...</header>
    `));

    // Stream main content as it becomes available
    const mainContent = await fetchMainContent();
    await writer.write(encoder.encode(`
          <main>${mainContent}</main>
    `));

    // Stream sidebar
    const sidebarContent = await fetchSidebarContent();
    await writer.write(encoder.encode(`
          <aside>${sidebarContent}</aside>
    `));

    // Complete the page
    await writer.write(encoder.encode(`
        </body>
      </html>
    `));

    await writer.close();
  })());

  return new Response(readable, {
    headers: { 'content-type': 'text/html' }
  });
}

Request Coalescing

Prevent thundering herd on cache misses:

// Request coalescing at the edge
const inflightRequests = new Map<string, Promise<Response>>();

export async function onRequest(context: EventContext): Promise<Response> {
  const cacheKey = context.request.url;

  // Check if request is already in-flight
  const inflight = inflightRequests.get(cacheKey);
  if (inflight) {
    // Wait for existing request
    const response = await inflight;
    return response.clone();
  }

  // Make new request and store promise
  const fetchPromise = fetchWithCache(context.request);
  inflightRequests.set(cacheKey, fetchPromise);

  try {
    const response = await fetchPromise;
    return response;
  } finally {
    // Clean up after completion
    inflightRequests.delete(cacheKey);
  }
}

async function fetchWithCache(request: Request): Promise<Response> {
  const cache = caches.default;

  let response = await cache.match(request);

  if (!response) {
    response = await fetch(request);

    // Cache successful responses
    if (response.ok) {
      const cloned = response.clone();
      cloned.headers.set('Cache-Control', 'public, max-age=60');
      await cache.put(request, cloned);
    }
  }

  return response;
}

Edge-Optimized Images

Transform and optimize images at the edge:

// Image optimization at the edge
export async function onRequest(context: EventContext): Promise<Response> {
  const url = new URL(context.request.url);

  if (!url.pathname.startsWith('/images/')) {
    return context.next();
  }

  // Parse optimization parameters
  const width = parseInt(url.searchParams.get('w') || '0');
  const quality = parseInt(url.searchParams.get('q') || '80');
  const format = url.searchParams.get('f') || 'auto';

  // Determine best format based on Accept header
  const accept = context.request.headers.get('accept') || '';
  const outputFormat = format === 'auto'
    ? accept.includes('image/avif') ? 'avif'
    : accept.includes('image/webp') ? 'webp'
    : 'jpeg'
    : format;

  // Use Cloudflare Image Resizing
  const imageUrl = `https://origin.com${url.pathname}`;

  const response = await fetch(imageUrl, {
    cf: {
      image: {
        width: width || undefined,
        quality,
        format: outputFormat
      }
    }
  });

  // Add cache headers
  const headers = new Headers(response.headers);
  headers.set('Cache-Control', 'public, max-age=31536000, immutable');
  headers.set('Vary', 'Accept');

  return new Response(response.body, {
    status: response.status,
    headers
  });
}

---

Testing Edge Functions

Comprehensive testing strategies for edge code.

Local Development

Run edge functions locally:

// Miniflare for local Cloudflare Workers testing
import { Miniflare } from 'miniflare';

const mf = new Miniflare({
  script: `
    export default {
      async fetch(request, env) {
        return new Response('Hello from edge!');
      }
    }
  `,
  modules: true,
  kvNamespaces: ['MY_KV'],
});

const response = await mf.dispatchFetch('http://localhost/');
console.log(await response.text()); // "Hello from edge!"

Unit Testing

Test edge functions in isolation:

// Jest tests for edge functions
import { unstable_dev } from 'wrangler';

describe('Edge API', () => {
  let worker: any;

  beforeAll(async () => {
    worker = await unstable_dev('src/index.ts', {
      experimental: { disableExperimentalWarning: true }
    });
  });

  afterAll(async () => {
    await worker.stop();
  });

  test('returns personalized greeting', async () => {
    const response = await worker.fetch('/api/greet?name=World');
    const text = await response.text();

    expect(response.status).toBe(200);
    expect(text).toBe('Hello, World!');
  });

  test('handles missing parameters', async () => {
    const response = await worker.fetch('/api/greet');
    const text = await response.text();

    expect(text).toBe('Hello, Guest!');
  });
});

Integration Testing

Test edge functions with real dependencies:

// Integration tests with KV storage
describe('Edge Cache', () => {
  let mf: Miniflare;
  let kv: any;

  beforeEach(async () => {
    mf = new Miniflare({
      scriptPath: './src/index.ts',
      modules: true,
      kvNamespaces: ['CACHE']
    });

    kv = await mf.getKVNamespace('CACHE');
  });

  test('caches API responses', async () => {
    // First request - cache miss
    const response1 = await mf.dispatchFetch('http://localhost/api/data');
    expect(response1.headers.get('x-cache')).toBe('MISS');

    // Second request - cache hit
    const response2 = await mf.dispatchFetch('http://localhost/api/data');
    expect(response2.headers.get('x-cache')).toBe('HIT');

    // Verify data is in KV
    const cached = await kv.get('/api/data', 'json');
    expect(cached).toBeDefined();
  });
});

---

Security Considerations

Edge computing introduces unique security challenges.

Input Validation at the Edge

Validate and sanitize all inputs:

// Input validation middleware
export async function middleware(request: NextRequest) {
  const url = new URL(request.url);

  // Validate query parameters
  for (const [key, value] of url.searchParams) {
    if (!isValidParameter(key, value)) {
      return new Response('Bad Request', { status: 400 });
    }
  }

  // Validate request body for POST/PUT
  if (['POST', 'PUT', 'PATCH'].includes(request.method)) {
    try {
      const body = await request.json();

      if (!validateRequestBody(body)) {
        return new Response('Invalid request body', { status: 400 });
      }
    } catch {
      return new Response('Invalid JSON', { status: 400 });
    }
  }

  return NextResponse.next();
}

function isValidParameter(key: string, value: string): boolean {
  // Length limits
  if (key.length > 64 || value.length > 1024) return false;

  // Character validation
  if (!/^[\w-]+$/.test(key)) return false;

  // SQL injection patterns
  const sqlPatterns = /('|"|;|--|\b(SELECT|INSERT|UPDATE|DELETE|DROP)\b)/i;
  if (sqlPatterns.test(value)) return false;

  return true;
}

Rate Limiting

Implement rate limiting at the edge:

// Edge rate limiting with Cloudflare KV
interface Env {
  RATE_LIMITS: KVNamespace;
}

export default {
  async fetch(request: Request, env: Env): Promise<Response> {
    const clientIP = request.headers.get('cf-connecting-ip') || 'unknown';
    const windowKey = `ratelimit:${clientIP}:${Math.floor(Date.now() / 60000)}`;

    // Get current count
    const current = await env.RATE_LIMITS.get(windowKey);
    const count = current ? parseInt(current) : 0;

    // Check limit (100 requests per minute)
    if (count >= 100) {
      return new Response('Rate limit exceeded', {
        status: 429,
        headers: {
          'Retry-After': '60',
          'X-RateLimit-Limit': '100',
          'X-RateLimit-Remaining': '0'
        }
      });
    }

    // Increment counter
    await env.RATE_LIMITS.put(windowKey, String(count + 1), {
      expirationTtl: 120  // 2 minute TTL
    });

    // Process request
    const response = await fetch(request);
    const modifiedResponse = new Response(response.body, response);

    modifiedResponse.headers.set('X-RateLimit-Limit', '100');
    modifiedResponse.headers.set('X-RateLimit-Remaining', String(99 - count));

    return modifiedResponse;
  }
};

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Conclusion: Embracing Edge-First Development

Edge computing represents the future of web development. As applications demand lower latency, higher personalization, and global reach, edge computing provides the architecture to deliver exceptional user experiences.

Key Takeaways

1. Choose the right platform: Vercel for Next.js, Cloudflare for complex workloads, Deno for TypeScript-first development
2. Think edge-first: Design applications with edge computation in mind from the start
3. Leverage edge data: Use KV stores and Durable Objects for stateful edge applications
4. Optimize for streaming: Stream responses to improve perceived performance
5. Test thoroughly: Local development and integration testing are essential

The Edge Computing Future

As we move through 2026, edge computing will continue to evolve:

• AI at the edge: Machine learning inference running on edge nodes
• WebAssembly expansion: More languages compiled to run on edge platforms
• Deeper integrations: Tighter coupling between frontend frameworks and edge runtimes

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Sources:

• Cloudflare Workers Documentation
• Vercel Edge Functions
• Deno Deploy Documentation
• AWS Lambda@Edge Developer Guide
• Web Almanac: CDN Chapter