Serverless architecture is a cloud computing execution model where the cloud provider dynamically manages server infrastructure, allowing developers to focus solely on writing and deploying code without server management concerns.

Core characteristics:

• No server management: Cloud provider handles all infrastructure provisioning, scaling, and maintenance
• Event-driven execution: Functions execute only in response to specific triggers or events
• Automatic scaling: Resources scale from zero to thousands of concurrent executions automatically
• Pay-per-use pricing: Billing based only on actual execution time and resource consumption
• Stateless functions: Each function execution is independent with no persistent state

Key differences from traditional architecture:

The main components include:

1. Functions as a Service (FaaS): Core compute units (AWS Lambda, Azure Functions)
2. API Gateway: Manages HTTP requests and routing to functions
3. Event Sources: Triggers that invoke functions (databases, queues, HTTP requests)
4. Storage Services: Databases and file storage (DynamoDB, S3)
5. Message Queues: Asynchronous communication between services
6. Authentication & Authorization: Identity management services
7. Monitoring & Logging: Observability tools for tracking performance
   These components work together to create a fully managed, event-driven application architecture.

Function as a Service (FaaS) is a serverless computing model where developers deploy individual functions that execute in response to events. The cloud provider manages all infrastructure aspects.
Key characteristics:

• Event-triggered: Functions execute only when triggered by events
• Stateless: Each execution is independent with no persistent state
• Auto-scaling: Automatically scales from zero to thousands of concurrent executions
• Short-lived: Functions have execution time limits (e.g., 15 minutes for AWS Lambda)
• Pay-per-invocation: Billing based on actual executions and compute time
  Examples include AWS Lambda, Google Cloud Functions, and Azure Functions. FaaS is ideal for microservices, API backends, data processing, and event-driven workflows.

AWS Lambda is Amazon's Function as a Service offering that runs code in response to events without provisioning servers. It automatically manages compute resources, scaling, and availability.
How it works:

1. Deploy code: Upload function code in supported languages (Python, Node.js, Java, etc.)
2. Configure triggers: Set up event sources (API Gateway, S3, DynamoDB)
3. Execution: Lambda creates container instances when events trigger functions
4. Auto-scaling: Automatically scales concurrent executions based on demand
5. Billing: Pay for compute time in 1ms increments
   Lambda handles infrastructure management, security patching, monitoring, and logging, allowing developers to focus solely on application logic.

Event-driven architecture in serverless is a design pattern where functions execute in response to events from various sources, creating loosely coupled, scalable systems.
Key concepts:

• Events: Triggers that initiate function execution (HTTP requests, file uploads, database changes)
• Event sources: Services that generate events (API Gateway, S3, DynamoDB)
• Event handlers: Functions that process specific event types
• Asynchronous processing: Events can be processed independently and in parallel
  Benefits:
• Loose coupling: Services don't need direct knowledge of each other
• Scalability: Each component scales independently
• Resilience: Failure in one component doesn't affect others
• Flexibility: Easy to add new event handlers without modifying existing code
  Example flow:

1. User uploads file to S3
2. S3 generates an event
3. Lambda function processes the file
4. Function writes results to DynamoDB
5. DynamoDB triggers another function for notifications