BossTimer-Mod
Server owners who run timed events can use BossTimer-Mod, a Fabric mod that shows named countdown timers as boss bars and runs commands when they start or end.
What it does
Admins create named countdown timers in a simple JSON config, and each timer can start with commands. A running timer appears as a live boss bar whose progress and remaining time update in real time. Timers can carry messages that fire at chosen remaining times, such as a warning when ten seconds are left, and commands can run before or after a timer ends. A player who joins while a timer is already running is synced to it at once.
The mod covers server restart warnings, event countdowns and scheduled announcements. It needs fabric-permissions-api, and it works alongside permission systems such as LuckPerms. Server owners install it, and players connect with no copy of their own. BossTimer-Mod is open source under the GNU General Public License v3.0 only, and 2.1.1 for 1.21.11 is the latest Fabric build.
Key features
Named countdown timers
Timers are defined by name in a JSON config, so several can be kept for different events and announcements.
Live boss bar display
Each running timer is shown with Minecraft's boss bar, with progress and remaining time updated continuously.
Trigger messages
Messages can fire at specific remaining times, for example when ten seconds are left in a countdown.
Commands before and after
Commands can run when a timer starts and when it ends, which lets a server chain actions onto a countdown.
Late join sync
Players who connect while a timer is running are synced to it automatically and see the same remaining time.
Compatibility
Latest build for each game version and loader.
1.21.x11 of 11 versions with builds
Only full game releases are shown. This mod publishes no snapshot builds.
Requirements
Dependencies declared by the latest file for each loader.
Required 1
Use cases
Who it’s for: Server owners and administrators who want timed boss bar countdowns with commands, on a server that uses a permission system.
How it compares
TimerDisplay Mod is a client-side only Fabric mod under the MIT License, so it changes only what each player sees. FlowHud is also client-side only, under All rights reserved. Chronos Timer is client-side only, open source under the MIT License, and built only for 1.21.11, so BossTimer-Mod differs by running on the server and triggering commands.
| Mod | Loaders | Game versions | Environment | Updated |
|---|---|---|---|---|
| BossTimer-Mod | Fabric | 1.21.1 – 1.21.11 | Server-side only | 2026-01-19 |
| TimerDisplay Mod | Fabric | 1.21.1 – 1.21.11 | Client-side only | 2026-04-12 |
| FlowHud | Fabric | 1.21.1 – 1.21.11 | Client-side only | 2026-02-01 |
| Chronos Timer | Fabric | 1.21.11 | Client-side only | 2026-08-01 |
Questions
Does BossTimer-Mod need to be installed on player clients?
What does BossTimer-Mod require?
Which game version is the latest BossTimer-Mod build for?
In the catalog
BossTimer-Mod is one of 8,499 Technology mods on ModsFinder, and one of 4,201 Technology mods for Fabric. 19,862 mods support Minecraft 1.21.11.
Similar mods
What the author says
BossTimer is a lightweight, server-side Fabric mod that lets server owners create and run configurable countdown timers displayed using Minecraft’s boss bar. It’s fully server-side, requires no client mods, and integrates with permission systems like LuckPerms.
Official listing
- Modrinth page
- modrinth.com/mod/bosstimer-mod
- Owner
- FreeSpinner09
- Published
- 2026-01-19
- Updated on Modrinth
- 2026-01-19
- Facts verified
- 2026-10-15