Trial Vault Forecast
by itzSelestia
Trial Vault Forecast predicts the rewards of trial chamber vaults on a multiplayer server, by tracking the server's loot sequence from observed vault openings.
What it does
The Fabric mod is a client-side only utility for Minecraft 1.21.11. It forecasts the drops of trial chamber vaults: the world seed fixes the reward sequences, and the mod works out where the server currently stands in each sequence. Normal vaults and ominous vaults keep independent sequences, so each is synchronized on its own. Fabric API is required to run it. The mod is open source under the GNU General Public License v3.0 or later, and its source code is public.
Two ways exist to build the sequences. The fast method recreates the RandomSequence loot generation in code within the mod itself. Players pick up loot immediately after an opened vault ejects its reward, so the mod can convert the drop and compare it with the generated sequence. A new, lightly used server usually needs only a few thousand drops to synchronize, while older, busy servers need a larger sequence because their current position lies far ahead.
Key features
Vault reward forecast
The mod lists upcoming rewards for normal and ominous vaults, so a player can see what the server will drop next.
Position tracking
Each observed opening removes candidate positions until one remains, and the predictor then knows the current position.
Find command
The find command searches forward from the synchronized position for a chosen reward, such as tridents or heavy cores.
Configurable unknown openings
A set number of unseen vault openings can sit between two known observations, which covers vaults opened by other players.
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
Vault HUD is a client-side only Fabric mod for 1.21.8 – 1.21.11, released under All rights reserved and not open source. Weather Forecast HUD is also client-side only for 1.21.8 – 1.21.11, under the MIT License and not open source, and it forecasts weather instead of vault rewards. Trial Cooldown runs on the server alone for 1.21 and is open source under the GNU Affero General Public License v3.0 only.
| Mod | Loaders | Game versions | Environment | Updated |
|---|---|---|---|---|
| Trial Vault Forecast | Fabric | 1.21.11 | Client-side only | 2026-08-17 |
| Vault HUD | Fabric | 1.21.8 – 1.21.11 | Client-side only | 2026-08-14 |
| Weather Forecast HUD | Fabric | 1.21.8 – 1.21.11 | Client-side only | 2026-06-09 |
| Trial Cooldown | Fabric | 1.21 | Server-side only | 2024-08-05 |
Questions
Does Trial Vault Forecast need Fabric API?
Does the mod have to be installed on the server?
Why does a server need several thousand drops before the forecast works?
In the catalog
Trial Vault Forecast is one of 36,990 Utility mods on ModsFinder, and one of 25,772 Utility mods for Fabric. 19,862 mods support Minecraft 1.21.11.
More from itzSelestia
Similar mods
What the author says
The count is applied separately to both sequences, not divided between them. For a new or lightly used server, several thousand drops should normally be enough. Older or highly active servers may require a larger sequence because the current global position could already be far into it.
Official listing
- Modrinth page
- modrinth.com/mod/trial-vault-forecast
- Owner
- itzSelestia
- Published
- 2026-08-17
- Updated on Modrinth
- 2026-08-17
- Facts verified
- 2026-10-15