Cheat sheetDS-05

Serverless

Distributed & Scalable / Serverless

Ship functions, not servers: FaaS like Lambda runs your code on event triggers, scales per-request automatically, and bills only for what runs.

01
FaaS + managedDeploy functions (Lambda) plus provider-run queues, storage, and databases.
02
Event triggersHTTP, file upload, queue message, or timer invokes the function — no event, no run.
03
Auto-scale + pay-per-useN events spin up N instances; idle costs nothing.
04
Cold starts / fitFirst idle call pays init latency; best for spiky glue, weak for steady heavy jobs.
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Reach for serverless on bursty, event-driven, short-lived work. Weigh cold starts and reserved-capacity economics for steady, latency-critical loads.

Good fitS3 upload triggers a Lambda that makes thumbnails; ten uploads run ten instances in parallel.
Weak fitA 24/7 high-utilization transcoding farm may be cheaper on reserved compute.
trigger: S3 upload -> Lambda(makeThumbnail)
scale: 10 events -> 10 instances (automatic)
cost: pay per invocation + duration; idle = 0
serverlessfaaslambdacold-startevent-triggerpay-per-use
review in 6d