You must have the world seed for this mod to work!

Slime Chunk Viewer is a highly configurable and simple mod that renders slime chunks on a server using the world seed.

Using the seed, you can find the slime chunks and highlight them with this mod! You can also change the color, opacity, outline, etc. (as seen below)

Make sure you have Fabric API, Mod Menu and Cloth Config

There are NO plans for this mod to be backported or ported to Forge.