Free Server Saver
by KURONAMI
On a low-memory NeoForge server, Free Server Saver watches JVM heap pressure and scales back expensive server work in stages before conditions become an emergency.
What it does
The mod targets slowdowns caused by high heap occupancy. After a 20-second startup warm-up it checks heap use about every two seconds, and when measured pressure rises it reduces the work that is most costly to the server. The default thresholds are set so that intervention starts gently and only escalates as memory stays tight. The goal is to keep a low-memory world responsive instead of letting it stall.
The reductions are scoped. Boss mobs, mobs carrying custom names, leashed or tamed animals, and other entities that persist are never targeted by the destructive measures. Random ticks on crops, leaves, snow and fire are the kind of work that can be changed.
Free Server Saver is a server mod for NeoForge 1.21.1 only. It is published under All rights reserved and is not open source, and its public links cover the source code. The first release was published on 2026-05-14 and the latest file, 0.1.1+neoforge-1.21.1, on 2026-08-07. Anyone running a server should keep a copy of the world before turning on any of these features, since the current release has not been tested on a live production server.
Key features
Staged heap response
Heap pressure is measured periodically, and the mod scales back expensive work in stages instead of reacting all at once.
Protected entities
Bosses, named mobs, leashed and tamed mobs and other persistent entities are left out of destructive intervention.
Modules that step aside
At startup the mod disables specific overlapping modules and records each disabled module in the startup log.
Emergency tier cleanup
The emergency tier removes eligible distant mobs and quarantines faulty entity data, but only after repeated failures.
Compatibility
Latest build for each game version and loader.
Only full game releases are shown. This mod publishes no snapshot builds.
Use cases
Who it’s for: The mod is aimed at server owners running NeoForge 1.21.1 who have memory limits and see lag tied to heap occupancy. Players who only join a server do not need to install it.
Questions
Which loader and version does Free Server Saver support?
Who can use the fss commands?
Does the mod change entities that matter to players?
In the catalog
Free Server Saver is one of 3,545 Optimization mods on ModsFinder, and one of 1,250 Optimization mods for NeoForge. 32,366 mods support Minecraft 1.21.1.
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What the author says
Watch JVM heap pressure and scale back expensive server work in stages before low-memory conditions become an emergency. Free Server Saver targets slowdowns caused by high heap occupancy on low-memory servers. It does not fix network latency or every source of low TPS; its scope is the work it can reduce when…
Official listing
- Modrinth page
- modrinth.com/mod/free-server-saver
- Owner
- KURONAMI
- Published
- 2026-05-14
- Updated on Modrinth
- 2026-08-07
- Facts verified
- 2026-10-15