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How to identify the queue and cause
Read the queue and reason fields together in each x-death entry. The queue is the source queue for that particular dead-lettering event; it is not necessarily the first queue the message visited. The newest event appears first in the array.
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For the first and latest event across the message’s history, RabbitMQ also provides x-first-death-queue and x-last-death-queue. Their associated reason and exchange headers are x-first-death-reason, x-first-death-exchange, x-last-death-reason, and x-last-death-exchange. First-death values are set once; last-death values change as later events occur. RabbitMQ’s dead-letter exchange documentation describes these fields.
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What each x-death entry contains
queue: the queue the message was dead-lettered from.reason: the recorded cause.count: the number of occurrences for that queue-and-reason pair.time: the time of the first event represented by that pair.exchange: the exchange to which the message had been published before the first such event from that queue for that reason.routing-keys: the routing keys before the first such event.original-expiration, when present: the original AMQP 0.9.1 expiration property. RabbitMQ removes expiration during dead-lettering so that the message does not expire again after it is routed.
Because entries are compressed by the {Queue, Reason} pair, count is not a total number of deaths across every queue and cause. It counts repeats represented by that particular entry.
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What the reason values mean
RabbitMQ documents four reason labels for AMQP 0.9.1 dead-letter history:
rejected: a consumer rejected or negatively acknowledged the message without requeuing it. This is the reason most directly tied to an explicit consumer decision.expired: the message’s time-to-live elapsed. Expiration processing differs between classic and quorum queues; quorum queues dead-letter expired messages when they reach the head of the queue. See RabbitMQ’s TTL and expiration documentation.maxlen: a queue’s maximum-length condition caused the message to be dropped or dead-lettered, depending on configuration.delivery_limit: a quorum queue returned the message more times than its configured delivery limit.
Dead-letter routing requires a dead-letter exchange (DLX) to be configured. Without one, a rejected message may be dropped rather than routed elsewhere. Queue expiration is different from message expiration: when an entire queue expires, its messages are not dead-lettered. These distinctions are documented in the RabbitMQ 3.13 DLX documentation.
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Read the header in the context of protocol and version
AMQP 0.9.1 and AMQP 1.0 use different metadata
The x-death header applies to RabbitMQ’s AMQP 0.9.1 protocol. With AMQP 1.0, the corresponding history is carried in the x-opt-deaths message annotation, with protocol-specific field names. Its entries include first-time and last-time, and may include ttl. Do not assume that a client library displays AMQP field types or timestamps in the same way across protocols. RabbitMQ documents AMQP 1.0 at rabbitmq.com/docs/amqp.
RabbitMQ 4.x and republished client headers
RabbitMQ 4.x continues to set and update broker-managed x-death when the broker dead-letters a message, including after a client rejection. However, RabbitMQ 4.x no longer interprets an AMQP 0.9.1 x-death header supplied by a client when that client republishes a message. Applications that republish messages and need their own retry counter should store it in a separate header rather than relying on the broker to increment client-provided history. This behavior is stated in the RabbitMQ 4.0.1 release notes.
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A practical way to debug a dead-letter path
- Confirm which protocol the connection uses. For AMQP 0.9.1, inspect
x-death; for AMQP 1.0, inspectx-opt-deaths. - Start with the first
x-deathentry, which is the most recent event, and note itsqueueandreason. - Check
countto see how many times that same queue-and-reason combination is represented. Compare other entries separately; the count is not global. - Use the first/last death queue and reason headers when you need the endpoints of the message’s recorded dead-letter history rather than one event’s source queue.
- Interpret the cause against the queue’s configuration and consumer behavior: rejection without requeue, message TTL, maximum length, or a quorum queue delivery limit.
- If an application republishes messages on RabbitMQ 4.x, distinguish broker-generated history from client-supplied retry metadata.
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