RabbitMQ : Difference between "message-ttl" and "expiration"

Question

What is the real difference between expiration and message-ttl in RabbitMQ?

I've read the documentation (https://www.rabbitmq.com/ttl.html) but still isn't clear.

Answer 1

message-ttl is set on a queue. You can bind multiple exchanges to the same queue. All messages which are routed to the queue will get this message-ttl set. expiration is set on a message by the sender. If the message is routed to a queue which has a message-ttl the lower of both values is applied.