TL;DR
Serverless architecture is model where you don't manage servers. Functions run on demand, you pay only for usage. Ideal for API, microservices and apps with variable traffic. Here's when to use serverless in 2026.
Who this is for
- Developers building API and microservices
- Companies looking for infrastructure savings
- Startups with variable traffic
Keyword (SEO)
serverless architecture, aws lambda, vercel functions, serverless when to use, cloud functions
What is serverless?
Serverless is model where:
- You don't manage servers
- Functions run on demand
- You pay only for usage (pay-per-use)
- Automatic scaling
Main platforms:
- AWS Lambda
- Vercel Functions
- Netlify Functions
- Google Cloud Functions
- Azure Functions
Serverless benefits
1. Lower costs
Pay-per-use:
- Pay only for executed functions
- No costs for idle time
- Ideal for variable traffic
Example:
- Traditional server: $50/month (24/7)
- Serverless: $5/month (only usage)
2. Automatic scaling
No configuration:
- Scales automatically
- Handles traffic spikes
- No limits (theoretically)
3. Faster development
Less management:
- No server configuration
- No system updates
- Focus on code
4. High availability
Built-in:
- Automatic redundancy
- Multi-region deployment
- Failover handling
When to use serverless?
1. API endpoints
Ideal for:
- REST API
- GraphQL resolvers
- Webhooks
- External integrations
Example:
// Vercel Function
export default async function handler(req, res) {
const data = await fetch('https://api.example.com/data');
res.json(await data.json());
}
2. Microservices
Ideal for:
- Small, independent services
- Event-driven architecture
- Background jobs
3. Variable traffic
Ideal for:
- Startups
- MVP
- Seasonal apps
- Event-based apps
4. Background processing
Ideal for:
- Image processing
- Email sending
- Data transformation
- Scheduled tasks
When NOT to use serverless?
1. Long executions
Limitations:
- AWS Lambda: 15 minutes max
- Vercel: 10 seconds (Hobby), 60 seconds (Pro)
- Netlify: 10 seconds (Free), 26 seconds (Pro)
Alternative:
- Traditional servers
- Containers (Docker)
- VPS
2. Constant, high traffic
Costs:
- With constant traffic traditional server may be cheaper
- Serverless may be more expensive with high usage
Example:
- 1M requests/month: serverless $20
- Traditional server: $10/month
3. Stateful applications
Problem:
- Serverless is stateless
- No local storage
- Need to use external databases
Alternative:
- Traditional servers
- Containers with persistent storage
4. Real-time applications
Limitations:
- WebSockets may be problematic
- Long-polling may exceed timeout
Alternative:
- Dedicated servers
- WebSocket services (Pusher, Ably)
Serverless platforms
1. Vercel
For:
- Next.js applications
- React applications
- Static sites with API
Features:
- Zero configuration
- Edge functions
- Automatic deployments
Pricing:
- Hobby: free (limitations)
- Pro: $20/month
2. AWS Lambda
For:
- Enterprise applications
- Complex architectures
- AWS ecosystem
Features:
- Most flexibility
- Integration with AWS services
- Many languages (Node.js, Python, Go, Java)
Pricing:
- Pay-per-use: $0.20 per 1M requests
3. Netlify Functions
For:
- JAMstack applications
- Static sites with API
- Serverless functions
Features:
- Simple deployment
- Netlify integration
- Edge functions
Pricing:
- Free: 125K requests/month
- Pro: $19/month
Best practices
1. Cold start optimization
Problem:
- First call may be slow (cold start)
- Runtime initialization
Solutions:
- Keep functions warm (scheduled ping)
- Minimize dependencies
- Use provisioned concurrency (AWS)
2. Error handling
Important:
- Retry logic
- Dead letter queues
- Monitoring and alerting
3. Security
Best practices:
- Environment variables for secrets
- IAM roles (AWS)
- Rate limiting
- Input validation
4. Monitoring
Tools:
- AWS CloudWatch
- Vercel Analytics
- Datadog
- New Relic
Cost optimization
1. Minimize execution time
Ways:
- Optimize code
- Cache responses
- Use CDN for static resources
2. Right-sizing
Choose appropriate:
- Memory allocation
- Timeout settings
- Region (close to users)
3. Reserved capacity
AWS:
- Provisioned concurrency
- Savings plans
- Reserved instances (for other services)
FAQ
Is serverless always cheaper?
No. For constant, high traffic traditional server may be cheaper. Serverless best for variable traffic.
How long can serverless function run?
Depends on platform: AWS Lambda 15 minutes, Vercel 10-60 seconds, Netlify 10-26 seconds. For longer tasks use traditional servers.
Is serverless secure?
Yes, if properly configured. Use environment variables, IAM roles, rate limiting and input validation.