FaaS
Function as a Service
ELI5 — The Vibe Check
FaaS is when you write a tiny function and deploy it to the cloud, and it only runs (and charges you) when someone calls it. No server sitting idle burning money. It's like a vending machine — nobody pays for electricity when nobody's buying. AWS Lambda is the most famous FaaS.
Real Talk
Function as a Service is an event-driven cloud execution model where developers deploy individual functions that run in stateless containers. The provider auto-scales, manages infrastructure, and charges only for execution time and invocations. Examples: AWS Lambda, GCP Cloud Functions, Azure Functions, Cloudflare Workers.
Show Me The Code
// AWS Lambda handler
export const handler = async (event) => {
const name = event.queryStringParameters?.name ?? 'World';
return {
statusCode: 200,
body: JSON.stringify({ message: `Hello, ${name}!` })
};
};
When You'll Hear This
"We use FaaS for the image resizing — it only runs when someone uploads." / "FaaS has cold start latency if the function hasn't been called recently."
Related Terms
Cloud Function
A cloud function is a piece of code you deploy to the cloud that runs when triggered — by an HTTP request, a file upload, a timer, or another event.
Cold Start
A cold start is the delay you get when a serverless function hasn't been used for a while and the cloud needs to spin up a fresh container to run it.
Edge Function
Edge functions run your code at the CDN edge — meaning close to the user, not in some faraway data center.
Lambda
AWS Lambda is where you upload a function and AWS runs it when something happens — an HTTP request, a file upload, a database change.
PaaS (Platform as a Service)
PaaS is when someone else handles the boring server stuff (OS, security patches, networking) and you just throw your code at it.
Serverless
Serverless doesn't mean there are no servers — it means YOU don't have to think about servers. Someone else manages them, scales them, and patches them.