NATS Messaging

NATS is an open-source messaging system (sometimes called message-oriented middleware). The NATS server is written in the Go programming language. Client libraries to interface with the server are available for dozens of major programming languages. The core design principles of NATS are performance, scalability, and ease of use.
Synadia develops and provides support for NATS. NATS was originally developed by Derek Collison as the messaging control plane for Cloud Foundry and was written in Ruby. NATS was later ported to Go. 
The source code is released under the Apache 2.0 License. NATS consists of:
Microservices frameworks such as Micro, Mainflux, and Hemera rely on NATS as their messaging backbone.
Example.
Below is a sample connection string from a telnet connection to the demo.nats.io site:
telnet demo.nats.io 4222
Trying 107.170.221.32...
Connected to demo.nats.io.
Escape character is '^]'.