Serverless Computing: Functions as a Service Explained
Serverless computing (also called Functions as a Service, or FaaS) allows you to run code without managing servers. You deploy individual functions that are triggered by events — an HTTP request, a queue message, a file upload — and the cloud platform handles all underlying infrastructure: provisioning, scaling, and availability.
How Serverless Works
You write a function (a piece of code with a defined input and output), deploy it to a serverless platform, and configure what triggers it. The platform automatically scales from zero to thousands of concurrent executions based on demand, and you pay only for execution time — not for idle server capacity.
Benefits
- No server management: No patching, no capacity planning, no scaling configuration
- Automatic scaling: Scales from zero to peak and back, handling any level of traffic
- Pay-per-use: Pay only for actual execution time — ideal for intermittent workloads
- Low operational overhead: Focus on code, not infrastructure
Trade-offs and Limitations
- Cold starts: First invocation after idle may be slower as the function container initialises
- Execution time limits: Functions have maximum execution time limits (e.g. 15 minutes on AWS Lambda)
- Statelessness: Functions cannot maintain state between invocations — state must be in external storage
- Vendor lock-in: Serverless code tends to be tightly coupled to the cloud provider's platform
Use Cases
- Event processing (S3 upload triggers, queue workers)
- API backends for low-to-medium traffic applications
- Scheduled jobs (cron-based tasks)
- Data processing pipelines
- Webhook handlers