Evaluate the message against a rule or validation condition.
Messaging Channels
Dead Letter Channel
Move undeliverable messages to a separate channel that preserves failure context and supports investigation, repair and controlled replay.
What will the messaging system do with a message it cannot deliver?Adapted from Enterprise Integration Patterns under CC BY 3.0. The visualization and explanatory content on this page are original GateSift material.
Original GateSift visualization
How Dead Letter Channel works
A rule decides whether a message continues through the normal flow or is removed from it.
Candidate message
Dead Letter Channel
Accepted
Ignored / isolated
Apply Dead Letter Channel to separate useful messages from unwanted or invalid ones.
Forward accepted messages and explicitly handle the rejected path.
What this pattern helps you decide
Move undeliverable messages to a separate channel that preserves failure context and supports investigation, repair and controlled replay.
What happens when processing fails or the same message is delivered twice?
Where does state, correlation or routing configuration live?
How will operators trace the message and understand the decision path?
Where you may see it
- Azure Service Bus DLQ
- Storage Queue poison queue
- Logic Apps dead-letter workflow
How the analyzers can surface it
- Missing failure routes
- Retry and terminal-error handling
Pattern detection is contextual. GateSift should present these as architectural signals, not claim a pattern is implemented solely because one policy statement or adapter exists.
Source, licence and attribution
The pattern name and selected problem statement are adapted from Enterprise Integration Patterns by Gregor Hohpe and Bobby Woolf under CC BY 3.0. GateSift summaries, Azure mappings, analyzer guidance and diagrams are original. No endorsement by the original authors is implied.