Why We Chose Edge Functions for Our SaaS Platform

The Challenge

When building a global SaaS platform, latency is a critical factor that directly impacts user experience. Our users are distributed across multiple continents, and we needed a solution that could provide:

  • Consistent low-latency responses
  • Cost-effective scaling
  • Simple deployment process
  • Real-time data processing capabilities

Understanding Edge Functions

Edge Functions represent a paradigm shift in how we deploy and execute code. Unlike traditional serverless functions that run in a fixed region, Edge Functions execute at the network edge, closer to the user.

Key Benefits

  1. Reduced Latency

    Traditional Setup (US East):
Asia User -> US East -> Asia User
~300ms round trip

Edge Functions:
Asia User -> Asia Edge -> Asia User
~50ms round trip

  2. Cost Optimization

    • Pay only for actual compute time
    • No cold starts
    • Automatic scaling

  3. Global Presence

    • 300+ edge locations
    • Automatic region selection
    • No manual deployment needed

Performance Analysis

We conducted extensive testing across different regions to compare traditional serverless functions with Edge Functions.

Latency Comparison

// Example Edge Function
export const config = {
  runtime: 'edge'
}

export default async function handler(req: Request) {
  const start = performance.now()

  // Process request
  const data = await processRequest(req)

  const duration = performance.now() - start

  return new Response(
    JSON.stringify({
      data,
      metrics: { duration }
    }),
    {
      headers: {
        'Content-Type': 'application/json'
      }
    }
  )
}

Benchmark Results

| Region | Edge Function | Traditional Function | Improvement | | ------------- | ------------- | -------------------- | ----------- | | North America | 35ms | 85ms | 59% | | Europe | 42ms | 180ms | 77% | | Asia | 48ms | 320ms | 85% | | South America | 45ms | 250ms | 82% | | Australia | 51ms | 290ms | 82% |

Real-world Implementation

Authentication System

One of our first Edge Function implementations was the authentication system:

// app/api/auth/verify/route.ts
export const runtime = 'edge'

export async function POST(request: Request) {
  try {
    const { token } = await request.json()

    // Verify token at the edge
    const user = await verifyToken(token)

    // Generate session
    const session = await createEdgeSession(user)

    return new Response(JSON.stringify({ session }), {
      status: 200,
      headers: {
        'Content-Type': 'application/json'
      }
    })
  } catch (error) {
    return new Response(JSON.stringify({ error: 'Authentication failed' }), { status: 401 })
  }
}

Real-time Data Processing

We also use Edge Functions for real-time data processing:

// app/api/analytics/track/route.ts
export const runtime = 'edge'

export async function POST(request: Request) {
  const data = await request.json()

  // Process analytics at the edge
  await Promise.all([enrichEventData(data), storeEventData(data), triggerRealTimeAlerts(data)])

  return new Response(null, { status: 200 })
}

Cost Analysis

Traditional vs Edge Deployment

Monthly costs for 1 million requests:

Traditional Setup:
- Compute: $20
- Data Transfer: $40
- Multiple Regions: $180
Total: $240/month

Edge Functions:
- Compute: $25
- Data Transfer: $15
- Global Deployment: Included
Total: $40/month

Cost Optimization Tips

  1. Efficient Data Handling

    // Good: Minimal data transfer
return new Response(
  JSON.stringify({
    id: user.id,
    name: user.name
  })
)

// Bad: Excessive data transfer
return new Response(JSON.stringify(user))

  2. Smart Caching

    export const runtime = 'edge'

export async function GET() {
  // Use edge caching
  const cached = await caches.default.match(request)
  if (cached) return cached

  const response = await generateResponse()
  response.headers.set('Cache-Control', 's-maxage=60')

  return response
}

Challenges and Solutions

1. Database Connectivity

Challenge: Edge locations need fast database access.

Solution: Implemented connection pooling and read replicas:

// lib/database.ts
import { createPool } from '@neondatabase/serverless'

export const pool = createPool({
  connectionString: process.env.DATABASE_URL,
  maxConnections: 10,
  idleTimeout: 60000
})

2. State Management

Challenge: Maintaining state across edge locations.

Solution: Used distributed caching:

// lib/cache.ts
import { Upstash } from '@upstash/redis'

export const cache = new Upstash({
  url: process.env.UPSTASH_REDIS_URL,
  token: process.env.UPSTASH_REDIS_TOKEN
})

Migration Strategy

We followed a phased approach:

  1. Phase 1: Non-critical endpoints

    • Analytics
    • Feature flags
    • Health checks

  2. Phase 2: Authentication system

    • Token verification
    • Session management
    • User preferences

  3. Phase 3: Core functionality

    • API endpoints
    • Real-time features
    • Data processing

Monitoring and Observability

Implemented comprehensive monitoring:

// middleware.ts
export const config = {
  runtime: 'edge'
}

export default async function middleware(req: Request) {
  const start = performance.now()

  // Add tracking headers
  const response = await fetch(req)

  // Record metrics
  await recordMetrics({
    duration: performance.now() - start,
    path: new URL(req.url).pathname,
    status: response.status
  })

  return response
}

Conclusion

Edge Functions have proven to be a game-changer for our SaaS platform:

  • 80% average latency reduction
  • 83% cost reduction
  • Improved developer experience
  • Better user satisfaction

The combination of performance, cost-effectiveness, and simplified deployment makes Edge Functions an excellent choice for modern SaaS applications.

Future Considerations

  1. Enhanced Edge Computing

    • AI model deployment at the edge
    • Advanced data processing
    • Edge-based A/B testing

  2. Expanded Use Cases

    • Real-time collaboration features
    • Video processing
    • Complex computations

Resources