Best practices for Lambda durable functions using a fraud detection example

This article explains best practices for AWS Lambda durable functions using a fraud detection workflow example with human-in-the-loop approval.

• Design steps to be idempotent using external API keys or at-most-once semantics
• Prevent duplicate executions using DurableExecutionName for unique transaction identifiers
• Use intermediary Lambda functions to bypass 15-minute event source mapping limits
• Match timeout settings to invocation type (async for workflows exceeding 15 minutes)
• Execute concurrent operations with context.parallel() for multi-channel notifications
• Always configure callback timeouts with try/catch fallback logic for escalation
• Combine patterns: deduplication, idempotency keys, parallel execution, and timeouts

Lambda durable functions enable fault-tolerant multi-step workflows lasting up to one year without compute charges during suspension periods, ideal for approval processes and AI orchestration.