Dead-Letter Queues and Failure Handling
Messages can fail to process. Learn how dead-letter queues capture poison messages, and how to design retries and reprocessing for resilient event-driven systems.
The Problem of Failing Messages
In an event-driven system a message may fail repeatedly — bad data, a downstream outage, or a bug. Without a safety net, it can block the queue or be lost forever.
What is a Dead-Letter Queue?
A dead-letter queue (DLQ) is a separate queue that captures messages that could not be processed after a set number of attempts. This isolates poison messages without losing them.
All lessons in this course
- SQS for Decoupling Services
- SNS for Pub/Sub Messaging
- Lambda with SQS/SNS Triggers
- Dead-Letter Queues and Failure Handling