Serverless Architecture: When and How to Use It

Serverless architecture has become a popular choice for building modern applications without managing infrastructure. But when should you use it—and when should you not?

In this guide, we’ll explore serverless fundamentals, ideal use cases, and considerations before going all in.

What Is Serverless?

Serverless doesn’t mean “no servers”—it means you don’t manage them.

Key Characteristics:

• Function-as-a-Service (FaaS): Code runs in response to events
• Auto-scaling: No manual provisioning
• Pay-per-use: Billed by execution time
• Stateless: Functions don’t maintain local state between calls

Popular providers include AWS Lambda, Google Cloud Functions, Azure Functions, and Vercel Functions.

Serverless vs Traditional Architectures

Feature	Serverless	Traditional Servers
Scaling	Automatic	Manual or container-based
Cost	Pay-as-you-go	Always-on pricing
Setup	Minimal	OS, runtime, updates needed
Cold Starts	Yes (initial delay)	No
State Management	External (DBs, caches)	Local or external

When to Use Serverless

✅ Best Use Cases

1. Event-driven systems
   e.g., image processing after file upload

2. REST APIs & Microservices
   Combine with API Gateway for routing

3. Scheduled Jobs
   Cron-like functions with serverless schedulers

4. IoT / Edge Functions
   Quick responses to device input

5. Prototypes & MVPs
   Speed up development without infrastructure

Example: AWS Lambda with API Gateway

exports.handler = async (event) => {
  return {
    statusCode: 200,
    body: JSON.stringify({ message: 'Hello from Lambda!' }),
  }
}

Common Pitfalls to Avoid

❌ Cold Starts

• Delay during first invocation

• Mitigate with:

  • Provisioned concurrency
  • Keeping functions warm via pinging

❌ Vendor Lock-In

• AWS-specific features (DynamoDB, IAM) limit portability
• Use open frameworks: Serverless Framework, SST, OpenFaaS

❌ Stateful Dependencies

• Serverless is stateless
• Use cloud databases (DynamoDB, Firebase, etc.) or queues

❌ Poor Observability

• Logs and traces can be hard to track
• Use tools like AWS CloudWatch, Datadog, or Honeycomb

Deployment & Tooling

Popular Frameworks

• Serverless Framework
• SST
• AWS SAM
• Vercel Functions

Example with Serverless Framework

service: hello-api

provider:
  name: aws
  runtime: nodejs18.x

functions:
  hello:
    handler: handler.hello
    events:
      - http:
          path: hello
          method: get

npx serverless deploy

Monitoring & Performance

• Use X-Ray, CloudWatch Logs, or Sentry
• Minimize bundle size for faster cold starts
• Avoid large dependencies
• Split functions by responsibility

Cost Efficiency

Pros:

• No idle costs
• Free tiers (e.g., 1M Lambda requests/month)

Cons:

• Can be expensive with:

  • High memory/time usage
  • Large concurrency spikes

• Always benchmark cost vs traditional hosting

Alternatives to Consider

Use Case	Consider This
Long-running processes	Containers, ECS, EC2
Stateful sessions	EC2, Kubernetes
Realtime applications	WebSockets, EventBridge, Pub/Sub
Heavy data processing	AWS Batch, Step Functions

Conclusion

Serverless is a powerful model—but not a silver bullet. It’s perfect for lightweight, event-driven systems, APIs, and prototypes. But for stateful, complex, or long-lived processes, consider hybrid or container-based alternatives.

Understand the trade-offs, monitor usage, and design for stateless execution to get the most from serverless.

Resources

• AWS Lambda Docs
• Serverless Framework
• Real-world Serverless by theburningmonk
• Vercel Edge Functions

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Serverless lets you focus on product, not infrastructure. Follow my blog for deep dives into AWS Lambda, Vercel, and real-time cloud-native architectures.