Entityopt
Servers with thousands of entities can lag badly, and Entityopt is a Fabric server mod that slows down the processing of entities far from players.
What it does
Entityopt runs only on the server. Players join without installing anything, and the mod works on servers that already have many entities loaded. Mobs close to a player behave normally, while mobs far away are throttled, so the server stops spending time on hundreds of entities nobody can see. Named mobs, leashed animals and any mob being ridden are always left alone.
The dormancy system sorts entities by distance from the nearest player. Entities within 48 blocks run normally, entities between 48 and 96 blocks update less often, and entities beyond 96 blocks go dormant and do almost no work. When a player moves close again, a dormant entity wakes up at once and resumes normal behaviour. A few commands let server owners check where entities are clumping up, view live counts of active and dormant entities, toggle the dormancy system off, and remove nearby entities within a given radius.
Entityopt is published for Fabric only, across 11 release versions 1.21.1 – 1.21.11 under the MIT License. It is not open source. The issue tracker is public. Files are versioned per game release, and the latest file targets 1.21.11.
Key features
Distance-based throttling
Entities far from every player are slowed down, while mobs near players keep their normal behaviour.
Dormancy for distant entities
Entities beyond 96 blocks from any player go dormant and wake up immediately when a player comes close.
Protected entities
Named mobs, leashed animals and mobs being ridden are excluded from throttling and dormancy.
Diagnostic commands
Commands show hotspots where entities clump, live entity counts and dormancy stats for the server.
Entity purge
A purge command removes entities within a chosen radius when they get out of hand.
Gallery
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.
How it compares
Resolve Bridge is a Fabric mod for 1.21 – 1.21.11 under All rights reserved, so its source is not open. FeaMC runs on Fabric and NeoForge for 1.21.2 – 1.21.11 and is client-side only, so it does not help the server. Entity Purge is server-side only, open source under the MIT License, and covers 1.21.4 – 1.21.6 on Fabric and NeoForge. Entityopt focuses on dormancy for all 1.21.1 – 1.21.11 builds on Fabric.
| Mod | Loaders | Game versions | Environment | Updated |
|---|---|---|---|---|
| Entityopt | Fabric | 1.21.1 – 1.21.11 | Server-side only | 2026-04-28 |
| Resolve Bridge | Fabric | 1.21 – 1.21.11 | Not published | 2026-07-16 |
| FeaMC | Fabric and NeoForge | 1.21.2 – 1.21.11 | Client-side only | 2026-02-14 |
| Entity Purge | Fabric and NeoForge | 1.21.4 – 1.21.6 | Server-side only | 2025-07-10 |
Questions
Does Entityopt need to be installed on the client?
Does Entityopt work on NeoForge or Forge?
Can named mobs or ridden animals be slowed down?
In the catalog
Entityopt is one of 3,545 Optimization mods on ModsFinder, and one of 2,575 Optimization mods for Fabric. 19,862 mods support Minecraft 1.21.11.
Similar mods
What the author says
EntityOpt is a server-side Fabric mod for Minecraft 1.21.11 that helps cut down on entity lag. It works by putting mobs to sleep when no players are around, so your server isn't wasting time processing hundreds of entities that nobody can even see. Mobs near players behave completely normally; it's only the ones off…
Official listing
- Modrinth page
- modrinth.com/mod/entityopt
- Owner
- invest_trade_crypto
- Published
- 2026-04-27
- Updated on Modrinth
- 2026-04-28
- Facts verified
- 2026-10-15