Introduction
Serverless computing has revolutionized how we build and deploy applications. By abstracting away infrastructure management, developers can focus purely on code. However, "serverless" doesn't mean "no servers"—it means "no servers you have to manage."
Common Patterns
1. The API Gateway Pattern
This is the most common pattern. An API Gateway sits in front of your Lambda functions (or Vercel Functions), routing requests to the appropriate handler.
- Pros: Scalable, pay-per-use.
- Cons: Cold starts can introduce latency.
2. Event-Driven Architecture
Serverless shines in event-driven systems.
- A user uploads a file to S3.
- An event triggers a Lambda function to resize the image.
- Another function updates the database.
This decoupling allows for highly resilient systems.
3. The "Lambdalith"
Instead of hundreds of tiny functions, some teams prefer a "Lambdalith"—a single function that handles multiple routes (like a monolithic Express app wrapped in a Lambda).
- Pros: Easier local development, fewer cold starts (since the function stays warm more often).
- Cons: Larger bundle size, slower deployment.
Managing State
Serverless functions are stateless. You need external storage for state:
- Databases: Serverless-friendly DBs like Neon (Postgres), PlanetScale (MySQL), or DynamoDB.
- Redis: Upstash or Redis Cloud for caching and session management.
Cold Starts
The "cold start" problem occurs when a function is invoked after being idle. To mitigate this:
- Keep bundle sizes small.
- Use lighter runtimes (e.g., Edge Runtime).
- Use provisioned concurrency (if on AWS).
Conclusion
Serverless isn't a silver bullet, but for many web applications, it offers the best balance of cost, scalability, and developer velocity.
