How large messages can I send?
While the theoretical message size limit in RabbitMQ is 2GB up to 3.7.0, we don't recommend sending messages larger than 128MB, which is also the new max size limit in 3.8.0 and onward. Large messages are especially problematic when using mirrored queues in HA clusters and can cause memory and performance issues.
References:
https://github.com/rabbitmq/rabbitmq-server/issues/147#issuecomment-470882099
https://github.com/rabbitmq/rabbitmq-common/pull/289