NATS is an open-source messaging system (sometimes called message-oriented middleware).

Client libraries to interface with the server are available for dozens of major programming languages.

[2] The acronym NATS stands for Neural Autonomic Transport System.

NATS was originally developed by Derek Collison as the messaging control plane for Cloud Foundry and was written in Ruby.

'JetStream' is the (optionally enabled) built-in persistence layer that adds streaming, queues, at-least-once and exactly-once delivery guarantees, historical data replay, decoupled flow-control and key/value store functionalities to Core NATS.