About Fluidlogged API
From ModrinthA library mod that adds highly customizable fluidlogging to 1.12.2!
A library mod that adds highly customizable fluidlogging to 1.12.2!
Fluidlogging is a mechanic that's inspired by Vanilla's Waterlogging mechanic, and that functions very similarly. The main difference is that Fluidlogged API has support for non-source fluids and all modded fluids!
If you're a modpack developer wanting to add Fluidlogged API to a modpack distributed outside of CurseForge or Modrinth, use File Director to avoid reuploading Fluidlogged API's files.
Any blocks can be made fluidloggable or non-fluidloggable through Fluidlogged API's configs, however it does make certain types of blocks fluidloggable by default. Any properly coded modded variants of these blocks are supported by default. Mods may also add fluidloggable blocks from their end. To see the full list of fluidloggable blocks, run the /fluidlogged_api print command in-game to create text files containing all active fluidlogging information.
Along with this, Fluidlogged API will download and apply community configs! This is to minimize the amount of work that players must do to have complete fluidlogging across mods, but this behavior can be fully disabled in fluidlogged_api/general.cfg if desired.
Fluidlogged API also heavily improves fluid collision accuracy, and fixes various Vanilla and modded fluid-related issues. Some Vanilla bug fixes include:
- MC-2591 Walking over the corner of lava deals damage
- MC-4533 Water graphical glitch when connecting diagonally
- MC-68129 Smooth lighting doesn't work properly underwater
- MC-100886 Falling sand with ID of water or lava does not render
- MC-125771 Block selection not showing up underwater
- MC-127030 Flowing water attempts to connect to waterlogged blocks when it shouldn't
- MC-127108 Waterlogged blocks turn lava into obsidian or cobblestone on physically unconnected sides
- MC-127270 Visual water level inside waterlogged blocks does not adjust correctly
- MC-227302 Smooth lighting doesn't work properly on the water surface
| Known Incompatibilities | Known Solutions | | --- | --- | | Better Water Mesh | None. | | Corail Tombstone | Use Corail Tombstone v4.6.0 or later! | | Oceanic Expanse | Use Oceanic Expanse v1.2.0 or later! | | Phosphor | Use Alfheim or 燐/Hesperus instead! | | The Aether II | Phosphor comes bundled with The Aether II. Luckily there exists The Aether II: Phosphor Not Included, which does as the name suggests! | | Vintagium | Use Celeritas instead! |
Q / A:
How does this mod work?
Reading through the source code would be the best way of truly understanding the inner workings of this mod, but I'll describe a simplified version here:
For each block in the world, Vanilla has two features that get stored in each chunk: a required IBlockState and an optional TileEntity. Fluidlogged API adds a third feature that gets stored in each chunk: an optional FluidState, which stores the fluidlogged fluid if present.
This mod applies ASM (a bytecode manipulation library that's bundled with Forge) to allow Vanilla and Forge to properly read and make use of FluidStates.
Is this mod safe to add to existing worlds?
It's generally a good idea to always back up your worlds before adding any new mods. That being said, this mod doesn't change the behavior of IBlockStates, so adding it to existing worlds should be fine! Removing this mod from existing worlds should also be fine, just note that existing FluidStates will be removed and won't be recoverable upon doing so.
How do I use this mod's configs? How do I use this mod as a dependency?
This mod's wiki will eventually cover both of those topics, for now it only covers how to use this mod's config. If you want to use Fluidlogged API as a library (optional or required dependency), the best I can do until I finish the wiki is reference you to the source code of these other projects of mine: Campfire, Seared Ladder Backport, Subaquatic.
Highlights
From source dataGame versions
Built for Minecraft 1.12.2.
Loaders
Runs on Forge.
Footprint
Rated a light load on a server.
What kind of mod it is
From the catalogLibraries & compatibility
Foundations and fixes other mods build on. Usually installed because something else needs it.
Runs on your server
From source side supportModrinth lists Fluidlogged API as required on the server. Check its Modrinth page to see whether players need it too.
Compatibility
- Game
- Minecraft
- Loaders
- Forge
- Runs on
- Serverrequired on the server
- Game versions
- 1.12.2
Verified at the source
- ✓ModrinthOfficial listing, checked 2026-10-01Open ↗
- ✓Authorjbredwards, as published on Modrinth
- ✓LicenseLicenseRef-Custom-LicenseFree
