EnvironmentDetector (API)
by FelixFGF
Launcher detection for Fabric mods: EnvironmentDetector is a Fabric library that reports the launcher, modpack, loader and Minecraft version a game runs under.
What it does
A mod that needs to know where it is running can ask EnvironmentDetector for the platform, modpack instance, loader, environment and Minecraft version, and receive the answer through a small developer API. Detection reads the startup arguments of the game, the same information that normally appears in the logs at launch, so a launcher is identified from the JVM arguments, launch paths and runtime parameters it leaves behind. Modrinth-launched instances are recognized because that launcher usually injects Modrinth-related paths and identifiers into the runtime. The library does not depend on process names, which lets it avoid false positives and duplicate detections.
Quilt is handled as its own case. Quilt runs Fabric mods natively, and the library includes dedicated Quilt detection logic so that logs report Quilt instead of plain Fabric. A mod used through a compatibility layer can still detect the environment it runs in. Installation needs Fabric Loader, and the library is client-side only, so servers do not need it. Builds cover the range listed below, and the library is open source under the MIT License, with its source code public.
Key features
Launcher and modpack detection
Reports the launcher platform and the modpack instance a game was started from.
Loader and version reporting
Identifies the mod loader, including Quilt when it runs Fabric mods, and the Minecraft version in use.
Runtime-based detection
Reads startup arguments and launch paths instead of scanning running processes, avoiding false positives.
Placeholder developer API
A simple API lets other mods read the detected environment information with minimal setup.
Gallery
Compatibility
Latest build for each game version and loader.
1.21.x12 of 12 versions with builds
Only full game releases are shown. This mod publishes no snapshot builds.
Required by 1 mod
Use cases
Who it’s for: Fabric mod developers who need to know the launcher, modpack or loader at runtime, and modpack authors who want accurate environment information in their logs.
How it compares
Death analytics is a client-side Fabric mod for 1.21.1 under All rights reserved, so its files do not cover the full span of this library. PlaceholderMaker is a server-side Fabric mod for 1.21 – 1.21.4 under the GNU General Public License v3.0 only, and it does not target the client-side environment this library uses. Fabric Placeholder is open source under the Mozilla Public License 2.0, runs as an optional client or server mod, and covers rd-132211 – 26.3.
| Mod | Loaders | Game versions | Environment | Updated |
|---|---|---|---|---|
| EnvironmentDetector (API) | Fabric | 1.21 – 1.21.11 | Client-side only | 2026-05-29 |
| Death analytics | Fabric | 1.21.1 | Client-side only | 2026-06-05 |
| PlaceholderMaker | Fabric | 1.21 – 1.21.4 | Server-side only | 2025-01-27 |
| Fabric Placeholder | Fabric | rd-132211 – 26.3 | Client or server, optional | 2025-12-07 |
Questions
Does EnvironmentDetector need Fabric Loader?
Does a server need to install EnvironmentDetector?
Which Minecraft versions does EnvironmentDetector support?
In the catalog
EnvironmentDetector (API) is one of 3,514 Library mods on ModsFinder, and one of 2,348 Library mods for Fabric. 19,862 mods support Minecraft 1.21.11.
More from FelixFGF
Similar mods
What the author says
A lightweight and crash-safe Minecraft environment detection API for Fabric, Quilt and modern modpack launchers. The API does NOT deeply modify Minecraft internals and avoids complex mixins for detection logic.
Official listing
- Modrinth page
- modrinth.com/mod/environmentdetector-api
- Owner
- FelixFGF
- Published
- 2026-05-28
- Updated on Modrinth
- 2026-05-29
- Facts verified
- 2026-10-15