Lib39
ModA shared library that provides tools used by other mods.
Why gradeA
How grades workStrengths
Points lost
- Releases in only 3 of the last 24 months−4 points
- Some modpacks removed it−1 point
- Under 5 million downloads−1 point
All 11 criteria
Maintenance
4 points lost23 / 27Last releaseHow long ago the newest file came out, or an existing file was marked as working on a new Minecraft version.3 months ago (9 Aug 2026) 12 / 12Supports popular versionsWhether the project has a file for a Minecraft version that 15% or more of the popular mods updated in the last 6 months also support. A version many modpacks use, like 1.20.1 or 1.21.1, also counts after a release in the last 12 months.1.20.1 on Fabric and Quilt. 15% or more of the popular mods updated in the last 6 months also have files for 1.20.1. Latest Minecraft: 26.3. 9 / 9Regular releasesIn how many of the last 24 months a new file came out. Full points at 8 months.Releases in 3 of the last 24 months 2 / 6Stability
1 point lost14 / 15Removed from modpacksHow many modpacks removed it in a later version of the pack. We can only see this in modpacks with two or more versions. A pack that swaps it for another edition of the same project, or that is rebuilt from scratch, does not count.3 of the 20 modpacks with two or more versions removed it in a later one (15%) See the 3 modpacks9 / 10Quick fixesHow often a release needed a quick fix: a new release within 3 days to fix a problem in it.Not measured yet.Known conflictsHow many projects say they do not work with it, compared with how widely it is used. Packs, small projects, forks, ports, add-ons, alternatives and old versions do not count.None 5 / 5Transparency
Full points10 / 10Source codeWhether the project page links to its source code, so anyone can read what it does.git.sleeping.town 7 / 7Place to report problemsWhether the project page links to a place where players can report problems: an issue tracker.git.sleeping.town 3 / 3Popularity
1 point lost3 / 4DownloadsDownloads on Modrinth and CurseForge. Full points from 5 million.202,801 3 / 4Track record
Full points8 / 8AgeHow long the project has existed. It counts less when no new file came out recently.4.2 years, 22 releases 8 / 8Security
PassedFile checksThis check adds no points. It can only take points away.Our checks found nothing harmful in both latest files for recent Minecraft versions. See Security
57.7 of the 64 points that apply = 90 out of 100. The points above are rounded to whole numbers.
About
Lib39 is a modular library that separates useful utilities, mixins, and events developed for the Yttr content mod so other mod authors can reuse them. Its modules cover foundational utilities such as automatic registration and mixin discovery, mixins that remove vanilla limits on model rotations and recipe sizes, customizable splash text, and a networking system. For world and block behavior, Lib39 provides hooks for modifying surface rules and generating content during world-generation phases, temporary block phasing that hides rather than removes blocks, a system for building large prefab blocks, and an efficient graph-based network for pipes and similar connections. Other modules add glow effects through an additional world-rendering layer, items that keep ticking via random ticks, and camera and field-of-view events with raw attack and use hooks. Data and content tools include logical defaults for loot tables, automatic recipe unlocks when players acquire a specified item, new soaking and piston-smashing recipe types with EMI support, and support for XM, S3M, and MOD tracker music. Lib39 also includes tools for adding recipe and tag item substitutions, control hints, and fixes for particle rendering behind translucent blocks.
Written from Modrinth . How we write it
In-game changes
Changes the game's code in 14 areas, as a library other mods build on: Rendering and graphicsChanges 9 game code files in this area: drawing mobs, items, particles and textures on screen., Inventory and itemsChanges 8 game code files in this area: items, chests and other containers, crafting and enchanting., World renderingChanges 5 game code files in this area: drawing the terrain, sky, clouds and weather., Server and world logicChanges 5 game code files in this area: the world, commands, scoreboards, saved data and game rules., World generationChanges 4 game code files in this area: terrain, biomes and structures made when new land is created., PlayerChanges 4 game code files in this area: your character: movement, abilities, hunger and controls., Blocks and fluidsChanges 4 game code files in this area: how blocks, fluids and redstone work., SoundChanges 3 game code files in this area: playing sounds, music and the sound engine., Mobs and their behaviorChanges 3 game code files in this area: mobs, animals, villagers, projectiles and how they move and act., Networking and multiplayerChanges 2 game code files in this area: connections, the server list and what is sent between your game and a server., Game data and resourcesChanges 2 game code files in this area: recipes, tags, advancements, language files and other game data., Game coreChanges 2 game code files in this area: the main loop, lighting and other code the whole game uses., Chunk loading and storageChanges 1 game code file in this area: how the game loads, tracks, saves and unloads chunks. and User interfaceChanges 1 game code file in this area: menus, screens, tooltips, the chat window and the in-game overlay..
Adds no new blocks, items or other content.
Keeps all of vanilla Minecraft's textures, models and sounds.
Often used with it
See all 30Details
- Creator
- exaptations
- License
- MIT License
- Downloads
- 203K
- Created
- 16 Aug 2022
- Official pages
- Modrinth , CurseForge
- Links
- Source code , Issues , Wiki , Discord
Security
No harmful code found
We checked its files and read their code, without running it.
What it can do on your computer
- Connects to the internet
- It has code that can go online, for example to check for updates, load skins or send crash reports. Found in Lib39 (Core), a library it includes. See Privacy
- Creates settings files
- The mod keeps its settings in the config folder of your game, where you can change or delete them. Only in its files for Fabric 1.20.1.
Why we show this: a mod runs on your computer like any program, so harmful code in it can take your accounts or files. Our checks look for known signs of harm. They cannot prove that a file is harmless. In the grade: malware means no grade, and a Warning in a latest file for a recent Minecraft version lowers it.
How we checked
- FilesWe download the files from Modrinth or CurseForge and look at what is inside them and what their code can do, without running them. Fixed rules tell what is harmful.5 latest files: the newest file for each Minecraft version and loader. The answer above is about the 2 for recent versions. Recent versions: those released in the last 2 years, plus 1.20.1 and 1.21.1, among the most played in modpacks. See each file in Releases
- Their codeWe turn the code of the files back into readable code and follow what it does, without running it. This shows what it downloads, what it sends and where your login goes.Read without running it
- Author on ModrinthThe disclosure form on Modrinth, where the author declares that the project reads or edits things on your system outside the game. Since 13 Aug 2026, Modrinth's rules require it when this applies.Nothing declared about your system outside the game.
- Looked for, not foundWe looked for these in the file and did not find them.Folders outside the game, other programs, updating itself, the webcam or microphone, an AI service.
Privacy
We found nothing it sends about you
We read its code without running it: it contacts 1 web address while you play.
Like any connection, each address it contacts sees your IP address.
Why we show this: a mod can send things about you over the internet, like your player name or your login. Contacting an address to check for updates or download files sends nothing about you. Not in the grade: sending data can be normal for what a mod does.
How we checked
- Files readWe read the code without running it. We list each web address the code contacts while you play, and what it sends. Code that is never used is left out.The code of both files, for recent Minecraft versions. See each file in Releases
- Address built while the game runsThe code builds this address while the game runs: it is not written in the file.Purpose not known.
- Author on ModrinthThe disclosure form on Modrinth, where the author declares crash reports, usage data and advertisements. Since 13 Aug 2026, Modrinth's rules require it when a project collects data on its users or shows advertisements.Nothing declared about crash reports, usage data or advertisements.
AI
No sign that AI was used to make it
We looked for AI tools in its texts, files and images and found none.
No sign of AI in the game
We found no AI service, AI library or AI model file in its code.
Why we show this: some players and servers avoid projects made with AI, and AI in the game can send what you write to an online service. Not in the grade: using AI does not tell whether a project works well or is kept up to date.
How we checked
- Author on ModrinthThe disclosure form on Modrinth. Since 13 Aug 2026, Modrinth's rules require it when a substantial part of the code is AI output, when an asset is mainly AI output, or when the project or its page relies on generative AI.No AI content or AI features declared.
- Description and changelogsThe description, project page and newest changelogs: sentences saying an AI tool was used, and text pasted from an AI chat.Nothing found3 of 33 changelogs read
- Its filesFiles that AI coding tools leave behind (like AGENTS.md), and the texts inside the files you download.Nothing found
- Images in its filesHidden data in the images of the files you download, where AI image tools write their name and settings.Nothing found
- Code of the modThe code and files of the mod, read without running it: addresses of AI services, AI libraries, AI model files and a place for your own AI key.No AI service, AI library or AI model file187 code files read
Compatibility
See all 22 filesPoint at or tap a version to see its loaders.
Related projects
Projects that need Lib39 to work.
Modpacks using this project
Find modpacks with itModpacks that include Lib39 in at least one of their versions, most downloaded first.
Another Quality Modpack 2 - AQM2627K downloadslast version with it 12 Jul 2023
Prominence™ I (Legacy)223K downloadslast version with it 30 Oct 2023
Scavengers of Ancient Power15K downloadslast version with it 20 Jul 2023
The Kingdom of Daldar [New Adventure Remade - Fabric]15K downloadslast version with it 3 Jun 2023
Gregorian Nightmares13K downloadslast version with it 29 Jun 2025
Hexwoven9.5K downloadslast version with it 23 Oct 2026
Nugget Pack: Rebirthed7.5K downloadslast version with it 9 May 2023
Spectrum Essentials5.7K downloadslast version with it 19 Nov 2023Tinkerer's Quilt Modded3K downloadslast version with it 9 Jun 2023
Unclouded2.3K downloadslast version with it 10 Jul 2023Often in the same modpacks
Mods that modpacks often add together with Lib39. Share: how many of the modpacks with Lib39 also have that mod.
LithiumAModin 84% of the modpacks with Lib39
[Deprecated] Farmer's Delight [Fabric]-Modin 80% of the modpacks with Lib39
Create FabricBModin 80% of the modpacks with Lib39
Mod MenuAModin 80% of the modpacks with Lib39
FerriteCoreAModin 80% of the modpacks with Lib39
LazyDFU-Modin 76% of the modpacks with Lib39
Memory Leak Fix-Modin 76% of the modpacks with Lib39
Sodium ExtraAModin 76% of the modpacks with Lib39
Reese's Sodium OptionsAModin 76% of the modpacks with Lib39
Hex CastingAModin 72% of the modpacks with Lib39Latest files
The newest file for each Minecraft version and loader. The files for recent versions come first. Recent versions: those released in the last 2 years, plus 1.20.1 and 1.21.1, among the most played in modpacks.