Harpy Express AC
by NebulaJinxed
Harpy Express AC is a server-side anti-cheat add-on for Fabric that targets cheating inside the Harpy Express minigame, adding checks on jumping, item dropping and packet-based kills.
What it does
The add-on runs on the server alone, so players join without installing anything. It detects jumping, bouncing, swimming, levitation and teleport abuse, and it blocks item dropping and attacks that the minigame does not allow, including kills made without a knife and kills made on spectators. Operators with permission are exempt from these checks.
Killing oneself with a knife through manipulated packets is also prevented, and jumping and dropping items in creative mode still follow the rules that the checks enforce. Files target Fabric on 1.21.1 only and are published under All rights reserved, so the code is not open source.
Installation is a matter of placing the mod in the server mods folder and launching the game, with no configuration step described for the minigame itself. The license and the single-version target both matter for server owners deciding whether to host it.
Key features
Movement cheat detection
Jumping, bouncing, swimming, levitation and teleport abuse are detected on the server and flagged as cheating.
Item drop prevention
Players in the minigame cannot drop items, which closes a route for cheating during a round.
Knife kill checks
Kills made without a knife are blocked, and packet manipulation used to kill oneself with a knife is prevented.
Spectator protection
Attacks on spectators are stopped, so players who have been eliminated cannot be killed.
Compatibility
Latest build for each game version and loader.
Only full game releases are shown. This mod publishes no snapshot builds.
Use cases
Server hosting a minigame
A server running Harpy Express can add these checks so that rounds are played under the minigame's own rules.
Who it’s for: Server owners who host Harpy Express on Fabric 1.21.1 and want anti-cheat checks specific to that minigame. Players need no client mod.
How it compares
Harpy Express More Shooter Punishments is also a server-side only Fabric mod for 1.21.1 under All rights reserved, but it covers shooter punishments rather than movement and kill checks. kittyWathe and Starry Express both need the client and server, use the same Fabric 1.21.1 target and are also not open source. G'Express is the only open source option here, released under the GNU General Public License v3.0 or later, and it runs on client and server.
| Mod | Loaders | Game versions | Environment | Updated |
|---|---|---|---|---|
| Harpy Express AC | Fabric | 1.21.1 | Server-side only | 2026-08-26 |
| Harpy Express More Shooter Punishments | Fabric | 1.21.1 | Server-side only | 2025-12-30 |
| kittyWathe | Fabric | 1.21.1 | Client and server | 2026-03-10 |
| Starry Express | Fabric | 1.21.1 | Client and server | 2026-03-10 |
| G'Express | Fabric | 1.21.1 | Client and server | 2026-10-14 |
Questions
Does Harpy Express AC need to be installed by players?
Which game version does Harpy Express AC support?
Are operators affected by the checks?
In the catalog
Harpy Express AC is one of 2,135 Minigame mods on ModsFinder, and one of 1,454 Minigame mods for Fabric. 32,366 mods support Minecraft 1.21.1.
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Official listing
- Modrinth page
- modrinth.com/mod/harpy-express-ac
- Owner
- NebulaJinxed
- Published
- 2025-11-29
- Updated on Modrinth
- 2026-08-26
- Facts verified
- 2026-10-15