Every major AWS service operates on at-least-once semantics. SQS redelivers. Lambda retries. EventBridge replays. Without explicit idempotency guards, your system processes the same operation twice.
This video breaks down:
• 4 root causes of duplicate operations on AWS
• 3 patterns to fix them: idempotency keys, conditional writes, natural idempotency
• Real implementations with DynamoDB, Lambda Powertools, and SQS FIFO
• Live demos — each failure mode broken and fixed on real AWS infrastructure
The key insight most teams miss: SQS FIFO deduplication only prevents duplicate sends (5-minute window). It does NOT prevent duplicate processing. If your consumer crashes after writing but before deleting the message, FIFO doesn’t save you.
Watch: <a href="https://youtu.be/DqUyk6SXBT4" target="_blank" rel="noopener nofollow">https://youtu.be/DqUyk6SXBT4</a>

Joud Awad

AWS services operate on at-least-once delivery semantics, meaning SQS, Lambda, and EventBridge can all trigger duplicate processing. This video covers 4 root causes of duplicate operations, 3 patterns to prevent them (idempotency keys, conditional writes, natural idempotency), and live demos using DynamoDB, Lambda Powertools, and SQS FIFO. A key insight: SQS FIFO deduplication only prevents duplicate sends within a 5-minute window — it does not prevent duplicate processing if a consumer crashes after writing but before deleting the message.

Idempotency on AWS — Why Your Lambda Runs Twice and How to Fix It