Reservoir Fluid API
by redColmula55
Reservoir Fluid API is a Fabric library that gives mod developers a single framework for registering and tuning custom fluids in Minecraft 1.20.1.
What it does
Fluid creation on Fabric is handled through one registry. A fluid is set up with a single FluidSettings object that holds its properties, and the ExtendedFluid base class reduces the number of overrides a developer must write. Fluids can flow upwards as well as downwards, and a data-driven reaction system lets fluids interact with one another through data files rather than code. Developers can also register several bucket types and make them stackable, and entity movement in fluids no longer depends on tags.
Players see the results in game. Submerging fog can be customized, so each fluid can show its own color and density when the camera is under it. The mod requires Cloth Config API, which must be installed alongside it. Reservoir Fluid API is published for Fabric only, with a single game version, 1.20.1, and the latest file is v1.0-beta3+1.20.1, released on the beta channel. It is open source under the GNU Lesser General Public License v2.1 or later, and both the source code and the issue tracker are public. Installation covers the server and each player's game.
Key features
Custom fluid registry
Fluids are registered through a dedicated registry, so a mod can add its own liquids without patching vanilla fluid code.
Single settings object
All fluid properties are set through one FluidSettings object, which keeps fluid definitions short and consistent.
Upward flow
Fluids can flow upwards in addition to the usual downward and sideways movement.
Data-driven reactions
Reactions between fluids are defined in data files, so new interactions can be added without writing new code.
Stackable buckets
Several bucket types can be created for a fluid, and each one can be made stackable.
Submerging fog
The fog shown when the camera is underwater or under another fluid can be customized for each fluid.
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
How it compares
Fluid Levels is a Fabric mod for 1.20.1 – 1.21.11 with a client-side only environment, released under the MIT License and open source. Liquid Lab is a Fabric mod for 1.21.1 with a client and server environment, also MIT licensed and open source. LazyFluids is a Fabric server-side only mod for 1.20.1, under the MIT License, and it is not open source.
| Mod | Loaders | Game versions | Environment | Updated |
|---|---|---|---|---|
| Reservoir Fluid API | Fabric | 1.20.1 | Client and server | 2026-09-23 |
| Fluid Levels | Fabric | 1.20.1 – 1.21.11 | Client-side only | 2026-02-15 |
| Liquid Lab | Fabric | 1.21.1 | Client and server | 2026-10-14 |
| LazyFluids | Fabric | 1.20.1 | Server-side only | 2025-08-27 |
Questions
Does Reservoir Fluid API need Cloth Config API?
Does the library have to be installed on the server?
Can Reservoir Fluid API run on Forge or NeoForge?
In the catalog
Reservoir Fluid API 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.
More from redColmula55
Similar mods
Official listing
- Modrinth page
- modrinth.com/mod/rfapi
- Owner
- redColmula55
- Published
- 2026-08-12
- Updated on Modrinth
- 2026-09-23
- Facts verified
- 2026-10-15