A NATS system is usually identified by a standard URL with the nats or tls protocol, e.g. nats:// A NATS system can be a single server, a small cluster or a global super cluster. Throughout these examples we will rely on a single test server, provided by, at nats://, where 4222 is the default port for NATS.

NATS also supports secure connectivity using TLS via the tls protocol. Most clients support auto-detection of a secure connection using the URL protocol tls. There is also a demo server running TLS at tls:// The protocol requirement is being made optional for many client libraries, so that you can use as the URL and let the client and server resolve whether or not TLS is required.

There are numerous options for a NATS connection ranging from timeouts to reconnect settings.