Hollow Core
Hollow Core is a Kotlin-based modding library for Forge that gives other mod authors registration, packets, capabilities, events and generated assets.
What it does
Hollow Core is a Kotlin-based library meant for developers who build Minecraft mods. Its Universal Registration system registers blocks, items and block entities through Kotlin delegates instead of separate registry code, and its Universal Packet system serializes network packets automatically once they are marked with annotations. Universal Capabilities store data on entities, block entities, worlds and NBT, while the Universal EventBus system handles mod loader and basic game events.
Hollow Core also covers assets and configuration. It generates block and item models through an embedded resource pack, generates sounds.json entries automatically, and serializes objects to NBT with Kotlinx.Serialization. Its config system reads and writes TOML files based on the same serialization layer. Kotlin for Forge is required, and Hollow Engine is the one catalog mod listed as requiring Hollow Core.
The library is client and server, so the server and every player run it. It is published for Forge only, in four release versions 1.18.2 – 1.19.2, under the MIT License, and the code is open source. The latest file, 1.19.2-1.6.3 for 1.19.2, dates from 2024-07-29.
Key features
Universal registration
Blocks, items and block entities are registered through Kotlin delegates instead of separate registry code.
Annotated packets
Network packets are serialized and registered automatically once they carry the library's annotations.
Capabilities for data storage
Capabilities attach stored data to entities, block entities, worlds and NBT compounds.
Generated models and sounds
Block and item models and the sounds.json file are produced automatically from the mod's own definitions.
TOML configuration
Config files are written as TOML, built on the same Kotlinx.Serialization layer as the NBT code.
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
Cuneiform is a Forge-only library for 1.16.3 – 1.18.2, licensed under the GNU General Public License v3.0 or later, and it is open source. Kinecraft covers Fabric, Forge, NeoForge and Quilt for 1.16.5 – 1.21.5 under the MIT License, and a player can run it on either side, and neither side needs it. WrapperLib is client and server with Fabric, Forge and Quilt builds for 1.16.5 – 1.19.3, under the Mozilla Public License 2.0.
| Mod | Loaders | Game versions | Environment | Updated |
|---|---|---|---|---|
| Hollow Core | Forge | 1.18.2 – 1.19.2 | Client and server | 2024-07-29 |
| Cuneiform | Forge | 1.16.3 – 1.18.2 | Client and server | 2024-03-23 |
| Kinecraft | Fabric, Forge, NeoForge and Quilt | 1.16.5 – 1.21.5 | Client or server, optional | 2025-11-09 |
| WrapperLib | Fabric, Forge and Quilt | 1.16.5 – 1.19.3 | Client and server | 2023-01-24 |
Questions
Does Hollow Core need Kotlin for Forge installed?
Does the server need Hollow Core?
Which game versions does Hollow Core support?
In the catalog
Hollow Core is one of 3,514 Library mods on ModsFinder, and one of 1,576 Library mods for Forge. 12,559 mods support Minecraft 1.19.2.
More from Phase of Horizon
Similar mods
What the author says
HollowCore is a minecraft modding library by HollowHorizon. It is an easy to use and powerful library for easier creation of minecraft mods for Fabric, Forge and NeoForge.
Official listing
- Modrinth page
- modrinth.com/mod/hollowcore
- Owner
- Phase of Horizon
- Published
- 2023-08-30
- Updated on Modrinth
- 2024-07-29
- Facts verified
- 2026-10-15