Server Configuration

SteelMC is configured through a TOML configuration file located at config/config.toml. This page documents all server options.

World settings are documented in World Configuration.

Basic Settings

Option	Type	Default	Description
server.server_port	u16	25565	The port the server listens on
server.max_players	u32	20	Maximum players allowed simultaneously
server.allow_extended_view_distance	bool	false	Allow view_distance above vanilla’s 32-chunk cap, up to Steel’s 127-chunk cap
server.view_distance	u8	10	Maximum view distance in chunks. Normally 1-32, or 1-127 with extended opt-in
server.simulation_distance	u8	10	Maximum simulation distance in chunks. Must be less than or equal to view range
server.motd	String	"A Steel Server"	Message displayed in the server list

Note

If you go beyond 32 chunks of view distance, vanilla clients still need a client-side mod that allows larger render distances.

Threads Settings

Optional worker counts for server thread pools. 0 or omitted uses each pool’s automatic default.

Option	Type	Default	Description
server.threads.main_runtime	usize	0	Worker threads for the primary Tokio runtime. 0 or omitted for default/auto.
server.threads.chunk_runtime	usize	0	Worker threads for the chunk Tokio runtime.
server.threads.chunk_generation	usize	0	Worker threads for the Rayon chunk generation pool.

These settings are only useful when you want to balance CPU use manually, for example to leave capacity for other processes on the same machine.

Security Settings

Option	Type	Default	Description
server.online_mode	bool	true	Use Mojang authentication for player verification
server.auth_server	String	omitted	Optional hasJoined endpoint for online mode. Omit to use Mojang
server.profile_server	String	omitted	Optional name-to-profile lookup endpoint. Omit to use Mojang’s profile service
server.services_server	String	omitted	Optional public-key endpoint for secure chat validation. Omit to use Mojang
server.encryption	bool	true	Enable encryption for client-server communication
server.allow_flight	bool	false	Allow unauthorized client flight in vanilla movement checks
server.enforce_secure_chat	bool	false	Enforce secure chat. Requires online_mode = true and encryption = true

Caution

Disabling online_mode allows unauthenticated clients to connect. Only disable it for private networks or development.

For debugging and bots it’s recommended to disable encryption (only for testing!)

Chat Settings

Option	Type	Default	Description
server.chat_spam_threshold_seconds	i32	10	Vanilla chat spam threshold window in seconds. Values <= 0 disable throttling
server.command_spam_threshold_seconds	i32	10	Vanilla command spam threshold window in seconds. Values <= 0 disable throttling

Favicon Settings

Option	Type	Default	Description
server.use_favicon	bool	true	Whether to use a custom favicon
server.favicon	String	"config/favicon.png"	Path to favicon file (64x64 PNG)

Compression Settings

Network compression reduces bandwidth usage at the cost of CPU.

Option	Type	Default	Valid Range	Description
server.compression.threshold	u32	256	>=256	Packet size threshold for compression
server.compression.level	i32	4	1-9	Compression level (1=fast, 9=best)

The [server.compression] table is optional. If it is omitted, compression is disabled.

Server Links

Server links are displayed in the multiplayer menu.

Option	Type	Default	Description
server.server_links.enable	bool	true	Enable server links feature
server.server_links.links	Array	4 links	List of links to display

See Server Links Guide for detailed configuration.

Logging Settings

Option	Type	Default	Description
log.log_path	String	"./.logs"	Directory for log files and command history
log.log_level	String	"info"	Log level: error, warn, info, debug, or trace
log.time	String	"uptime"	Time format: none, date, or uptime
log.module_path	bool	false	Whether the module path should be displayed
log.extra	bool	false	Whether extra log data should be displayed
log.log_file	bool	true	Whether logs should also be written to files
log.rotation_time	String	"daily"	File rotation: none, hourly, daily, weekly, or monthly
log.max_history	usize	50	Number of console commands saved in history

Example Configuration

/config/config.toml

[server]
server_port = 25565
max_players = 50
allow_extended_view_distance = false
view_distance = 12
simulation_distance = 10
online_mode = true
# auth_server = "https://sessionserver.mojang.com/session/minecraft/hasJoined"
# profile_server = "https://api.minecraftservices.com/minecraft/profile/lookup/name"
# services_server = "https://api.minecraftservices.com/publickeys"
encryption = true
allow_flight = false
motd = "Welcome to my Steel server!"
use_favicon = true
favicon = "config/favicon.png"
enforce_secure_chat = false
chat_spam_threshold_seconds = 10
command_spam_threshold_seconds = 10

[server.threads]
main_runtime = 0
chunk_runtime = 0
chunk_generation = 0

[server.compression]
threshold = 256
level = 4

[server.server_links]
enable = true

[[server.server_links.links]]
label = "bug_report"
url = "https://github.com/4lve/SteelMC/issues"

[log]
log_path = "./.logs"
log_level = "info"
time = "uptime"
module_path = false
extra = false
log_file = true
rotation_time = "daily"
max_history = 50

Validation Rules

The server validates configuration on startup:

• unknown fields are rejected
• server.view_distance must be between 1 and 32, or between 1 and 127 when server.allow_extended_view_distance is true
• server.simulation_distance must be less than or equal to server.view_distance
• server.auth_server, when set, must be an absolute http or https URL
• server.profile_server, when set, must be an absolute http or https URL
• server.services_server, when set, must be an absolute http or https URL
• server.compression.threshold must be at least 256
• server.compression.level must be between 1 and 9
• if server.enforce_secure_chat is true, both server.online_mode and server.encryption must be true
• log.log_level, log.time, and log.rotation_time must use one of their listed values

If validation fails, the server will exit with an error message.