StateObserver
Developers who need to track blockstate changes across a wide area can use StateObserver, a small library for Fabric, Forge and NeoForge.
What it does
StateObserver watches for changes to blockstates over a large area and reports them to other mods that depend on it. Its author describes it as very small and lightweight, with little performance cost at that scale. Players do not interact with it directly, since it only exists for developers to build on. Fabric API is required on Fabric. The environment is client and server, so the server and every player need it, and the code is released under the GNU Lesser General Public License v3.0 or later, which makes it open source. Files cover 1.18.2, 1.19.2, 1.20.1 and 1.21.1.
Key features
Blockstate observation
Reports changes to blockstates across a large area for other mods to react to.
Low overhead
Observes many blocks at once while keeping the cost small, according to its author.
Developer library
Built as a library for mod developers, with no in-game items, blocks or menus of its own.
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 1
Required by 1 mod
How it compares
Statement is a Fabric, Forge, NeoForge and Quilt library under the MIT License, covering 1.14.4 – 1.20.4 with an optional client or server environment. MultipartLib is a Fabric-only library for 1.19.2 under the MIT License, and Block Limit Fix is a server-side only MIT-licensed mod for 1.16.5 – 1.19.3.
| Mod | Loaders | Game versions | Environment | Updated |
|---|---|---|---|---|
| StateObserver | Fabric, Forge and NeoForge | 1.18.2 – 1.21.1 | Client and server | 2025-12-20 |
| Statement | Fabric, Forge, NeoForge and Quilt | 1.14.4 – 1.20.4 | Client or server, optional | 2023-12-28 |
| MultipartLib | Fabric | 1.19.2 | Client and server | 2023-06-08 |
| Block Limit Fix | Fabric, Forge and Quilt | 1.16.5 – 1.19.3 | Server-side only | 2023-10-05 |
Questions
Does a player need to install StateObserver?
Which loader does StateObserver need Fabric API for?
In the catalog
StateObserver is one of 3,514 Library mods on ModsFinder, and one of 2,348 Library mods for Fabric. 32,366 mods support Minecraft 1.21.1.
More from Favouriteless
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What the author says
StateObserver is a very small and lightweight library for observing blockstate changes across a large area without a large performance hit. If you're a player, don't worry about this mod! It's just a library for developers to use.
Official listing
- Modrinth page
- modrinth.com/mod/stateobserver
- Owner
- Favouriteless
- Published
- 2024-05-30
- Updated on Modrinth
- 2025-12-20
- Facts verified
- 2026-10-15