Function as a Service — execution model where code runs in stateless containers managed entirely by the cloud provider, billed per invocation and execution duration.

Latency penalty incurred when a function has no warm container available, requiring the platform to initialize a new execution environment including runtime and dependencies.

A previously-initialized execution environment retained by the platform for reuse, eliminating initialization overhead and reducing invocation latency to single-digit milliseconds.

Configuration that connects a stream or queue (Kinesis, SQS, DynamoDB Streams) to a Lambda function, allowing automatic invocation as records arrive without polling code.

Maximum number of simultaneous function executions within an account or region. AWS Lambda default is 1,000 per region; reserved concurrency allocates a fixed pool per function.

Pre-initialized execution environments that eliminate cold starts entirely, held ready at a fixed cost regardless of invocation volume — ideal for latency-sensitive endpoints.

AWS managed state machine service for orchestrating multi-step workflows. Uses Amazon States Language JSON to define sequences, parallel branches, error handlers, and wait states.

Serverless event bus routing events between AWS services, SaaS providers, and custom applications using declarative event patterns with schema registry and replay capability.

Destination (SQS queue or SNS topic) receiving events that a function fails to process after maximum retry attempts, enabling offline inspection and reprocessing without data loss.

ZIP archive containing shared libraries, custom runtimes, or configuration data, mounted into the function's execution environment at /opt to reduce deployment package sizes.

Lightweight function executing at CDN edge nodes geographically close to users, enabling sub-5ms response for auth, routing, A/B testing, and content personalization without origin trips.

Property ensuring that executing a function multiple times with the same input produces the same side effects as a single execution — critical given at-least-once delivery semantics in serverless.

Open-source deployment toolkit translating declarative YAML into cloud provider infrastructure — Lambda functions, API Gateway routes, IAM roles, event sources — across AWS, Azure, and GCP.

Serverless Application Model — AWS CloudFormation extension with simplified syntax for defining Lambda functions, API Gateway APIs, and DynamoDB tables, with local testing via sam local.

The runtime environment reused across warm invocations within the same container. Persists /tmp storage (512 MB), initialized SDK clients, and cached data between requests on the same instance.

Platform rate limiting applied when invocations exceed concurrency limits. Synchronous calls receive 429 TooManyRequests; async invocations enter a retry queue with exponential backoff up to 6 hours.

Azure Functions extension enabling stateful workflows through checkpointed orchestrator functions that replay deterministically, coordinating activities, timers, and human interaction patterns.

Kubernetes Event-Driven Autoscaling — open-source component scaling Kubernetes workloads based on external event sources (Kafka lag, queue depth, HTTP rate), bridging serverless patterns onto K8s.

Lambda async invocation routing: on-success and on-failure targets (SQS, SNS, Lambda, EventBridge) receiving enriched result records including request/response payloads for observability and error handling.

AWS Lambda feature for Java functions restoring pre-initialized snapshots at invocation time, reducing cold starts from seconds to milliseconds by caching the JVM state post-initialization.

Dedicated HTTPS endpoint for a Lambda function without API Gateway, supporting IAM or no-auth access, streaming response mode, and built-in CORS configuration for direct web client invocation.

IAM execution role assumed by the function at runtime, granting least-privilege access to AWS services via temporary STS credentials — eliminating long-lived secrets from serverless environments.