
Modrinth · Minecraft mod
Fly's config lib
Simplest JSON config lib to not repeat yourself :P
Quick answer
Which Fly's config lib release matches 1.21.1 Forge?
Fly's config lib 1.2.0 targets 1.21.1, 1.21.2, 1.21.3 with Forge. Installation on the client is optional. Installation on the dedicated server is optional. No extra mods listed for this file.
Where it goes
Is Fly's config lib required on the client, server, or both?
Installation on the client is optional. Installation on the dedicated server is optional.
The source marks this as usable on both the client and server.
What else does Fly's config lib 1.2.0 need?
1.2.0 on 1.21.1 Forge. Every mod below is checked against that same setup.
This file does not list any required mods. Do not add a library just because a different file uses it.
This file does not list any required or optional mods.
Before you install it
Add Fly's config lib without breaking your instance.
Built for Fly's config lib 1.2.0 on 1.21.1 Forge. Pick another file and the loader, install side or required mods may change.
- 01
Stick to this file
Use 1.2.0. It targets 1.21.1, 1.21.2, 1.21.3 with Forge; another release may have different loader, side or dependency requirements.
- 02
Bring the mods it needs
This file does not list any required mods. Do not add a library just because a different file uses it.
- 03
Put it on the correct side
Installation on the client is optional. Installation on the dedicated server is optional.
- 04
Pick the file you checked
Use the “Get this file” button beside 1.2.0. It opens that exact file at the source.
About this project
What does Fly's config lib add?
Fly's Config Lib
A shared configuration library for Fly's Minecraft mods providing JSON config management, registry helpers, and NBT pattern matching.
Features
- Load and save mod settings from a JSON file
- Automatically creates a default config file if none exists
- Detects when the config file is edited on disk and reloads it without restarting
- Backs up broken/corrupted config files with a timestamp before resetting to defaults
- Look up items, blocks, and entities by their in-game I
- Caches registry lookups so repeated lookups don't slow things down
- Match items by their NBT data (enchantments, custom names, written book authors, etc.)
- Partial NBT matching — only the tags you specify need to match, the rest are ignored
- Exact NBT matching — the item must have exactly the tags specified, nothing more
- List NBT matching — check if an item has at least one of the specified enchantments/tags
- Strict list matching — check if an item has all of the specified enchantments/tags
- Numeric NBT values match regardless of internal type
- Map config keys to values using either exact strings or regex patterns
- Extract parts of a matched string via capture groups and reuse them in the mapped value
Project description from Modrinth.
Pick your setup
Fly's config lib by Minecraft version and loader
Choose the version and loader you play, then open the matching release.
1.21.10
2 loader builds1.21.9
2 loader builds1.21.8
2 loader builds1.21.7
2 loader builds1.21.6
2 loader builds1.21.5
2 loader builds1.21.4
2 loader builds1.21.3
2 loader builds1.21.2
2 loader builds1.21.1
3 loader builds1.20.6
1 loader buildShowing the newest 12 of 18 game versions. Older files are in the list below.
Check the dependencies, then try the file in a copied instance before changing a world you care about.
Recent files
Fly's config lib versions and loaders
1.2.0
flysconfiglib-forge-1.21.1-1.2.0.jar
4 Aug 2026
Looking for an older file? The official Modrinth project page is in Resources.