Spawn Overlay
by Mrbysco
Spawn Overlay draws markers in the world that show where mobs can spawn, with several overlay types and adjustable polling and chunk radius settings.
What it does
Each overlay type highlights a different spawning condition. Always Spawning marks spaces where mobs appear regardless of the time of day, Night Spawning marks spaces that spawn mobs only at night, and Phantom Spawning marks the spaces above which phantoms appear. Prevent Spawning shows where light blocks spawning, and two slab-placement overlays show the positions for keeping regular Spiders and Ghasts from spawning.
The overlay is meant for players who build mob farms or want to see spawn rules without reading the source. Poll Interval sets the number of milliseconds between updates of the overlay, and Chunk Radius sets how many chunks around the player are displayed. Clients normally know nothing about structures, so the optional Structure Mode needs the mod on the server as well.
Spawn Overlay needs Fabric API on Fabric and Forge Config API Port on both loaders. Players need it in their own game, while a server can run without it. It is open source, and its source code and issue tracker are public. Files target 1.21.1, 26.1.2, 26.2 and 26.3, and the latest builds are 2.0.3 for 26.3.
Key features
Always Spawning overlay
Marks the spaces where mobs spawn no matter what the time of day is.
Night and phantom overlays
Separate markers show spawns limited to nighttime and the spaces above which phantoms appear.
Prevent Spawning overlay
Shows where light blocks mob spawning, so placement can be checked before building.
Adjustable update and radius
Poll Interval controls the milliseconds between overlay updates, and Chunk Radius sets the area shown around players.
Gallery
Compatibility
Latest build for each game version and loader.
Only full game releases are shown. This mod publishes no snapshot builds.
Requirements
Dependencies declared by the latest file for each loader.
Required 2
Use cases
Who it’s for: Players who build mob farms or study spawn mechanics, and server owners who want to allow Structure Mode.
How it compares
Assorted Light Overlay is client-side only, open source under the GNU General Public License v3.0 only, and published for 26.2, so it covers light rather than spawns. Simple Block Overlay is also client-side only and open source, but licensed under the GNU Lesser General Public License v3.0 only and built only for Fabric, across 1.20 – 26.2. Spawn Overlay supports both Fabric and NeoForge.
| Mod | Loaders | Game versions | Environment | Updated |
|---|---|---|---|---|
| Spawn Overlay | Fabric and NeoForge | 1.21.1 – 26.3 | Client required, server optional | 2026-09-29 |
| Assorted Light Overlay | Fabric and NeoForge | 26.2 | Client-side only | 2026-10-05 |
| Simple Block Overlay | Fabric | 1.20 – 26.2 | Client-side only | 2026-08-20 |
Questions
Does Spawn Overlay need Fabric API?
Do servers need Spawn Overlay installed?
Which versions does Spawn Overlay support?
In the catalog
Spawn Overlay is one of 36,990 Utility mods on ModsFinder, and one of 25,772 Utility mods for Fabric. 8,071 mods support Minecraft 26.3.
More from Mrbysco
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What the author says
Spawn Overlay is a mod that adds multiple types of overlays to visualize where mobs can spawn. There's base types of overlays in the mod, spawn overlays and optimizer overlays. ¹ Structure Mode requires the mod to be installed server-side! Clients normally know nothing about structures
Official listing
- Modrinth page
- modrinth.com/mod/spawn-overlay
- Owner
- Mrbysco
- Published
- 2026-08-19
- Updated on Modrinth
- 2026-09-29
- Facts verified
- 2026-10-15