Lambda

AWS Lambda is a serverless compute service: you upload a function, and AWS runs it in response to events without you managing any servers.

Common triggers:

• S3 events — new file lands in a bucket, Lambda processes it
• API Gateway — HTTP requests invoke a function directly
• Step Functions — Lambda as a step in a larger orchestrated workflow
• Schedules (EventBridge) — cron-like periodic invocation

You pay per invocation and per millisecond of execution time, not for idle capacity — useful for bursty or infrequent workloads where a always-on server would sit idle.

See also: Airflow