Settings

Settings

Celeris has one setting: the network compression level.

What it does

When Celeris sends data over the network, it can compress it first. The level sets how hard it tries.

Level	What happens
0	No compression. Least CPU work, most data sent.
1	The default. Fastest compression.
9	Smallest data sent. Most CPU work.

Levels in between trade CPU work for size. Higher numbers give smaller data, and use more CPU.

Only the sender's level matters. The level on a server controls what the server sends. The level on a player's game controls what that player sends. The two sides do not need to match.

Change it on NeoForge

In the game: open Mods, then Celeris, then Config. Change the value and save. It applies to the next packet.

In the file: open config/celeris-common.toml and set the value:

compressionLevel = 1

On newer NeoForge versions (26.3 and later), the file is named celeris-local.toml instead. If you edit the file by hand, restart the game or server.

Change it on Fabric

With Mod Menu: open Mods, then Celeris, then Config. Changes apply at once and are saved for you. You need Mod Menu for this screen.

In the file: Celeris creates config/celeris.properties the first time it starts. Open it and set:

compressionLevel=1

Restart the game or server after you edit this file by hand.

Allowed values

Use a whole number from 0 to 9.

On Fabric, a number outside that range is replaced by the nearest allowed value, 0 or 9, and a warning goes to the log. A value that is not a number is replaced by the default, 1.

Examples

The server CPU is busy, and bandwidth is not a concern. Use 0. Celeris does not compress the data it sends.

Players have slow connections, and the server has CPU to spare. Try a higher value, such as 5 or 9.

You are not sure. Keep the default, 1.