softwaremill/elasticmq
in-memory message queue system runs stand-alone (download), via Docker or embedded Amazon SQS-compatible interface fully asynchronous implementation, no blocking calls created and maintained by: ElasticMQ is a message queue system, offering an actor-based Scala and an SQS-compatible REST (query) interface. ElasticMQ follows the semantics of SQS. Messages are received by polling the queue.
https://github.com/softwaremill/elasticmq