What Is Serverless? A Beginner's Guide to Serverless Architecture

Serverless doesn't mean "no servers" — it means servers are no longer your problem. You write code, the cloud provider runs it. Server management, capacity planning, and scaling are entirely the provider's responsibility.

Two Categories

1. Function as a Service (FaaS)

Event-driven functions:

// AWS Lambda
exports.handler = async (event) => {
  const { userId } = JSON.parse(event.body);
  await sendWelcomeEmail(userId);
  return { statusCode: 200, body: 'Email sent' };
};

2. Backend as a Service (BaaS)

Ready-made backend services: Auth, database, storage, push notifications. Examples: Supabase, Firebase, AWS Amplify

Execution Model

Traditional: Server runs 24/7 (consumes resources even idle)
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Serverless: Runs only when requests come in
    ███    ██   ████     ██  ███    █████

Pros & Cons

✅ Advantages

• Zero server management
• Pay-per-use pricing (no traffic = no cost)
• Auto-scaling (0 to thousands instantly)
• Focus on business logic

❌ Disadvantages

• Cold starts (100ms-3s on first request)
• Vendor lock-in
• Execution limits (Lambda: 15 min max)
• Debugging difficulty
• Cost unpredictability with traffic spikes

Serverless Providers

| Provider | FaaS | BaaS | |----------|------|------| | AWS | Lambda | Amplify, DynamoDB | | Google Cloud | Cloud Functions | Firebase, Cloud Run | | Azure | Azure Functions | Static Web Apps | | Cloudflare | Workers | R2, D1, KV |

When to Use Serverless

✅ Yes — Event-driven workloads, irregular traffic, MVPs, API backends, cron jobs

❌ No — Continuous workloads, WebSockets, ultra-low latency, complex state, GPU/ML

Conclusion

Serverless dramatically improves development speed and cost efficiency when used correctly. But not every workload fits. Evaluate requirements and consider hybrid approaches.

Learn serverless and cloud architecture on the DevOps career path at LabLudus.