M0-DevTools
by M0diis
M0-DevTools is a client-side Fabric toolbox of overlays and tweaks for modders, builders and technical players, bundled into one mod.
What it does
The overlays draw information over the game world: light levels where mobs can spawn, redstone power levels and the order of redstone dust updates, slime chunks, biome boundaries, chunk borders, structure bounding boxes and command block details. Each one can be switched on when a player needs it.
Beyond overlays, the mod carries customizable behavior changes: particle tweaks that hide the player's own effect particles, rendering tweaks that hide the offhand item or entity models, environmental tweaks that disable Nether fog and rain effects, audio tweaks that mute selected sounds, and movement helpers. The author notes that some modules, such as X-Ray and Freecam, need the mod installed on the server as well.
Installation is for Fabric only. The files target 1.21.11 alone, and the latest one is j21-mc1.21.11-1.3.0-BETA, a beta release published on 2026-06-22. The client needs the mod, while the server can run without it. The code is open source under the MIT License, and the project began as a personal tool before the author decided to release it publicly.
Key features
Light level and mob spawning overlay
Shows light levels on the ground so builders can see which blocks prevent mob spawning.
Redstone power and update order overlays
Displays redstone power levels and the order in which redstone dust updates, which helps with BUD mechanics.
Slime chunk and biome border overlays
Highlights slime chunks for quick location and draws biome boundaries on the map.
Chunk and structure bounding box overlays
Outlines chunk borders for navigation and building, and shows structure bounding boxes.
Command block information overlay
Shows details of command blocks in the world, useful when debugging command setups.
Gallery
Compatibility
Latest build for each game version and loader.
Only full game releases are shown. This mod publishes no snapshot builds.
How it compares
Worldgen Devtools is open source under the MIT License, runs on Fabric and is published for 1.20.5 – 26.3 with the client or server optional. Light Level Overlay is client-side only, open source under the MIT License, and covers Fabric and NeoForge for 1.21.1 – 1.21.10. Custom Item Highlighter is client-side only, not open source and released under All rights reserved, for 1.21.11 – 26.2.
| Mod | Loaders | Game versions | Environment | Updated |
|---|---|---|---|---|
| M0-DevTools | Fabric | 1.21.11 | Client required, server optional | 2026-06-22 |
| Worldgen Devtools | Fabric | 1.20.5 – 26.3 | Client or server, optional | 2026-10-03 |
| Light Level Overlay | Fabric and NeoForge | 1.21.1 – 1.21.10 | Client-side only | 2026-01-14 |
| Custom Item Highlighter | Fabric | 1.21.11 – 26.2 | Client-side only | 2026-08-06 |
Questions
Does M0-DevTools need Fabric API?
Does the server need M0-DevTools?
Which game versions does M0-DevTools support?
In the catalog
M0-DevTools is one of 8,016 Management mods on ModsFinder, and one of 5,930 Management mods for Fabric. 19,862 mods support Minecraft 1.21.11.
Similar mods
What the author says
M0-Dev Tools is a client-side Fabric toolbox for Minecraft modders, builders, and technical players. It bundles overlays, HUDs, movement helpers, macros, scripting, and debugging tools into one mod. Certain modules such as X-Ray, Freecam will require the mod to be installed on the server as well.
Official listing
- Modrinth page
- modrinth.com/mod/m0-devtools
- Owner
- M0diis
- Published
- 2026-06-04
- Updated on Modrinth
- 2026-06-22
- Facts verified
- 2026-10-15