ModsFinder

AttachmentsAPI

by Sygikal

AttachmentsAPI is a Fabric library that lets other mods attach their own data to game objects such as players, entities and block entities.

FabricClient and serverAll rights reserved1.20.1

What it does

Mods that depend on it register data classes, and the library attaches those classes to target classes at runtime through ASM bytecode changes, without the dependent mod editing the game classes itself. It also covers the synchronization and persistence of the attached data. Realistic Human Pain and Suffering, Climbing and Rude Awakening require it. The server and every player need the mod installed. Only Fabric is supported, with the latest build 1.1.4.8 for 1.20.1, released 2025-09-02. The code is available publicly, but the mod is under All rights reserved and is not open source.

Key features

  1. Attachable data classes

    Other mods can declare a data class and attach it to a target class without modifying that class in their own source.

  2. Bytecode-based attachment

    Attachments are applied through ASM, so the target class gains the data handling directly when the game loads it.

  3. Synchronization and persistence

    The attached data is kept in sync between server and clients and is saved along with the world.

Compatibility

Latest build for each game version and loader.

1.20.11.1.4.8
ReleaseBetaAlphaNot available

Only full game releases are shown. This mod publishes no snapshot builds.

Required by 3 mods

Realistic Human Pain and Suffering1.20.1Climbing1.20.1Rude Awakening1.20.1

How it compares

Full comparison

Data Anchor is open source under the Mozilla Public License 2.0 and covers Fabric, Forge, NeoForge and Quilt for 1.20.1 – 26.3. AttachmentsAPI is Fabric only and not open source. RegistryEdit is open source under the MIT License for Fabric and Quilt 1.20 – 1.20.4, and it works on either side, and neither needs it. AttachmentsAPI needs both the client and the server.

ModLoadersGame versionsEnvironmentUpdated
AttachmentsAPIFabric1.20.1Client and server2025-09-02
Data AnchorFabric, Forge, NeoForge and Quilt1.20.1 – 26.3Client and server2026-09-19
RegistryEditFabric and Quilt1.20 – 1.20.4Client or server, optional2024-04-01

Questions

Does Climbing need AttachmentsAPI?

Yes. Climbing is one of the three catalog mods that require AttachmentsAPI, so it must be installed next to it on Fabric.

In the catalog

AttachmentsAPI is one of 3,514 Library mods on ModsFinder, and one of 2,348 Library mods for Fabric. 34,764 mods support Minecraft 1.20.1.

Library mods3,514Fabric modsMods for 1.20.134,764

More from Sygikal

All projects
Realistic Human Pain and Suffering1.20.1UltraLib1.20 – 1.21.10ABAttribute Backport1.20.1TabAPI1.20 – 1.20.6SkillZ1.20.1HotbarAPI1.20.1 – 1.21.10

Similar mods

Fabric API1.14 – 26.3Cloth Config API1.14 – 26.3YetAnotherConfigLib (YACL)1.19 – 26.3Architectury API1.16.5 – 26.3Just Enough Items (JEI)1.8 – 26.3Geckolib1.12.2 – 26.3

What the author says

This is a personal library I made to help with the creation and handling of data. It uses ASM magic to add any object straight into its target class and handles the synchronization and persistence of said data.
Sygikal, on the Modrinth page

Official listing

Owner
Sygikal
Published
2025-08-07
Updated on Modrinth
2025-09-02
Facts verified
2026-10-15

Tags

LibraryManagementUtilityStorage
Open on ModrinthCompare