ModsJava
Mob Spawn Indicator
Highlights block surfaces where hostile mobs can spawn using color-coded overlays. Free Minecraft Java mod for 1.21.1.
⬇ Download on Modrinth
Mob Spawn Indicator highlights valid mob spawn floors in your vicinity with color-coded overlays. It uses vanilla spawn rules, so it works on any server without needing to be installed server-side.
Features
- Color-coded overlays on valid spawn floors: red (danger), yellow (warn), green (safe)
- Configurable render distance, opacity, and which colors to display
- Settings GUI accessible from the Options screen or via commands
- Client-side only — works on vanilla servers, SMPs, and modded servers
Commands
/msi settings— open the settings GUI/msi toggle— toggle the overlay on/off/msi on|/msi off— enable or disable the overlay/msi reset— reset all settings to defaults
Configuration
Default keybind: J (toggle overlay)
Config file: config/msi-common.toml
| Option | Default | Description |
|---|---|---|
render_rad |
16 | Render distance in blocks |
overlay_opacity |
0.5 | Overlay transparency |
show_danger |
true | Show red overlay (valid spawn, no space for mobs) |
show_warn |
true | Show yellow overlay (valid spawn, 1 block space) |
show_safe |
false | Show green overlay (valid spawn, 2+ block space) |
Notes
- Uses vanilla Minecraft spawn rules: slabs, stairs, trapdoors, glass, and leaves are correctly excluded as non-spawnable
- Overlays update every 5 ticks
- Works in singleplayer, LAN, and multiplayer
Verified by MCModsHub
- Ships as msi-1.0.0.jar — drop this file into the mods folder
- Download size: 1.6 MB
- Download link checked 24 Aug 2026 — working
These come from our own check of the pack file, not from the source page.