What are the pros and cons of Serverless architecture? When should you choose Serverless?

What Serverless Is

Serverless doesn't mean no servers — it means developers don't manage servers. The cloud provider handles infrastructure provisioning, scaling, and maintenance; you just upload code.

Key services: AWS Lambda, Google Cloud Functions, Azure Functions

Advantages

Zero ops burden: No OS management, patching, or capacity planning

Auto-scaling: From zero to thousands of concurrent executions with no configuration

Pay-per-execution: Zero cost when idle (vs long-running EC2 instances)

Fast iteration: Deploy individual functions without managing an entire application

Disadvantages

Cold starts: First execution after idle periods has latency (typically 100ms-2s)

• Solutions: Provisioned Concurrency (pre-warmed instances), scheduled triggers to keep warm

Execution time limits: AWS Lambda max 15 minutes — not suitable for long-running tasks

Local development difficulty: Differences from cloud environment make debugging complex

Vendor lock-in: Deep dependency on the cloud provider's services and triggers

Observability challenges: Distributed functions make distributed tracing more complex

Good Serverless Use Cases

• Event-driven data processing (S3 upload triggers thumbnail generation)
• API backends (unstable traffic, clear peak patterns)
• Scheduled tasks (Cron jobs)
• Webhook handlers

Poor Serverless Use Cases

• Low-latency applications (cold starts are unacceptable)
• Long-running tasks
• High-throughput, sustained workloads (EC2/containers are more cost-effective)