Server configuration

Environment variables

Variable	Required	Purpose
BLITZ_RELAY_CONNECTION_KEY	Always	Passed to LiteNetLib to authenticate UDP connection requests.
BLITZ_RELAY_HTTP_ADMIN_TOKEN	When HTTP is enabled	Bearer token for protected HTTP administration endpoints.

Blank or whitespace-only required values prevent the server from starting. The HTTP admin token is not required when --disable-http is present.

Command-line options

Option	Alias	Default	Purpose
--port <port>	-p	7770	UDP relay port.
--http-port <port>		7771	HTTP API TCP port.
--disable-http		false	Does not create the HTTP API or listener.
--log-level <level>	-l	Information	Minimum console log level.
--cors <path>			JSON CORS configuration file.

Accepted log levels are Trace, Debug, Information, Warning, Error, and Critical.

CORS configuration

Without --cors, the HTTP API allows any origin, method, and request header. Credentials are not enabled.

{
  "allowedOrigins": ["https://admin.example.com"],
  "allowedMethods": ["GET", "POST", "PATCH", "DELETE"],
  "allowedHeaders": ["Authorization", "Content-Type"],
  "allowCredentials": false
}

Every property is optional. An omitted or empty origins, methods, or headers array allows any value for that category. Credentials are enabled only when allowedOrigins contains at least one explicit origin.

The server exits with code 1 if the CORS file is missing or cannot be deserialised.

Relay timing

Setting	Value
Event polling interval	15 ms
LiteNetLib update interval	15 ms
Ping interval	2 seconds
Peer disconnect timeout	30 seconds
Host claim timeout	10 seconds

Backpressure thresholds

For each recipient, unreliable relay traffic is dropped when its reliable queue contains at least 256 packets. A recipient is disconnected before another reliable relay packet is sent when its reliable queue contains at least 2,048 packets.

Unreliable frames that exceed LiteNetLib’s maximum unreliable packet size are dropped. Reliable frames may be fragmented by LiteNetLib.

Shutdown and exit codes

The UDP server and optional HTTP API share one application lifetime. Stopping either side stops the root application. Normal shutdown returns exit code 0; startup or hosted-service failure returns 1.