The NATS server has many flags to customize its behavior without having to write a configuration file.

The configuration flags revolve around:

  • Server Options

  • Logging

  • Authorization

  • TLS Security

  • Clustering

  • Information

Server Options


-a, --addr

Host address to bind to (default: - all interfaces).

-p, --port

NATS client port (default: 4222).

-P, --pid

File to store the process ID (PID).

-m, --http_port

HTTP port for monitoring dashboard (exclusive of --https_port).

-ms, --https_port

HTTPS port monitoring for monitoring dashboard (exclusive of --http_port).

-c, --config

Path to NATS server configuration file.

-sl, --signal

Send a signal to nats-server process. See process signaling.


Client HostPort to advertise to other servers.


Test configuration and exit

JetStream Options


-js, --jetstream

Enable JetStream functionality.

-sd, --store_dir

Set the storage directory.

Authentication Options

The following options control straightforward authentication:



Required username for connections (exclusive of --auth).


Required password for connections (exclusive of --auth).


Required authorization token for connections (exclusive of --user and --password).

See token authentication, and username/password for more information.

Logging Options

The following flags are available on the server to configure logging:


-l, --log

File to redirect log output

-T, --logtime

Specify -T=false to disable timestamping log entries

-s, --syslog

Log to syslog or windows event log

-r, --remote_syslog

The syslog server address, like udp://localhost:514

-D, --debug

Enable debugging output

-V, --trace

Enable protocol trace log messages


Verbose trace (traces system account as well)


Enable both debug and protocol trace messages


Debug and verbose trace (traces system account as well)


Maximum printable length for traced messages. 0 for unlimited

You can read more about logging configuration here.

TLS Options



Enable TLS, do not verify clients


Server certificate file


Private key for server certificate


Enable client TLS certificate verification


Client certificate CA for verification

You can read more about tls configuration here.

Cluster Options

The following flags are available on the server to configure clustering:



Comma-separated list of cluster URLs to solicit and connect


Cluster URL for clustering requests


Do not advertise known cluster information to clients


Cluster URL to advertise to other servers


For implicit routes, number of connect retries

You can read more about clustering configuration here.

Common Options


-h, --help

Show this message

-v, --version

Show version


TLS help

Last updated