// modpack server guide
Slimes Adventure server hosting & setup guide
A Slimes Adventure server needs Java 21 and about 6–8 GB of RAM for up to 15 players.
Tensura: that time i got reincarnated as a slime modpack with many features
Summary from Slimes Adventure on Modrinth.
Slimes Adventure is a Forge and Fabric modpack for Minecraft 1.21.1 (older versions go back to 1.16.5) with 125 mods. We'd pick our Premium plan (8 GB) for it.
Quick facts
| Loader | Forge and Fabric |
|---|---|
| Minecraft versions | 1.21.1, 1.19.2, 1.16.5 |
| Java needed | Java 21 for Minecraft 1.21.1Older pack versions: Java 17 for 1.19.2; Java 8 for 1.16.5. Java version chart. |
| Mods | 125 modsCounted from the pack's file list on Modrinth. None are marked client-only. |
| RAM | About 4.5–5 GB for 1–3 playersBy player count. |
| Downloads | 2,019,102 on Modrinth |
| Last updated | September 11, 2026 (version 1.13.4) |
| First published | July 23, 2023 on Modrinth |
| Server support | Required: the pack has mods that must run on the server. |
| Server pack | Not published separatelyHow to build the server. |
| Modrinth tags | adventure, combat, magic, challenging, optimization |
Slimes Adventure server files
No. Slimes Adventure has no separate server pack on Modrinth or CurseForge (we checked CurseForge on October 5, 2026), so the server is built from the .mrpack: the Forge or Fabric server for Minecraft 1.21.1, plus the pack's overrides folder and the server-side mods its modrinth.index.json lists. A modpack installer does this for you; our guide shows how to make a server for a modpack with no server pack.
How much RAM does a Slimes Adventure server need?
| Players online | RAM | DSN plan |
|---|---|---|
| 1–3 players | About 4.5–5 GB | Premium (8 GB) |
| 4–8 players | About 5–6.5 GB | Premium (8 GB) |
| 9–15 players | About 6–8 GB | Premium (8 GB) |
Estimated from 125 mods on the server with our RAM calculator, not measured: low end if players stay together, high end if they spread out.
Set Java's heap (-Xmx) 10–15% under the RAM you have, about -Xmx7000M on 8 GB. Forge 1.21.1 reads it from user_jvm_args.txt: uncomment the -Xmx line. RAM guide.
Slimes Adventure server requirements
| Java | Java 21 |
|---|---|
| Loader | Forge or Fabric for Minecraft 1.21.1 |
| CPU | Fast single-core speed (one main thread). |
| RAM | About 4.5–8 GB for 1–15 players (table above) |
| Disk | The server files, a growing world and backups |
| Network | TCP port 25565 open to players |
Recommended plan
Our pick for Slimes Adventure
Premium
8 GB RAM · planned launch price $30/month
At about 125 mods this is a mid-size pack, and 8 GB gives it room for the mods plus the chunks your players load.
Ordering is closed until we relaunch. We aren't taking orders or payments while we move to new hardware. Join the launch list and we'll email you when Premium servers open.
More than 15 players, or lots exploring at once? Go up to Heavy (12 GB). Not sure? Email hello@dsnservers.com.
Planned launch price in USD, billed monthly once ordering opens, with a 7-day refund window.
How to make a Slimes Adventure server on your own PC
What's specific to Slimes Adventure, step by step. The full walkthrough for any pack: how to make a modded Minecraft server.
- Install Java 21.
Check with
java -version. Java version chart. - Get the server files.
Build them from the .mrpack, as in server files above.
- Start it and accept the EULA.
Run the start script in the server files, or the
run.sh/run.batthe Forge 1.21.1 installer writes, then seteula=trueineula.txtif you accept Mojang's EULA (EULA step). - Set the RAM with
-Xmx, sized from the table above. - Let friends connect: forward TCP 25565, or use a tunnel or host behind CGNAT (can't connect?).
Or run Slimes Adventure on DSN
Once we relaunch (join the launch list), on DSN you'd install Slimes Adventure from the panel's Modrinth modpack installer (version 1.13.4), pick Java 21 on the Startup tab and accept the EULA in the console. No port forwarding.
How to play Slimes Adventure with friends
Each player installs Slimes Adventure version 1.13.4 with the Modrinth App or Prism Launcher, the same version as the server, and adds the server's address under Multiplayer.
Different versions of Slimes Adventure on the server and a client show up as Mismatched mod channel list or mod rejections. Why friends can't join, timeouts included.
Lag and performance on Slimes Adventure
Can't keep up! Is the server overloaded? means ticks take longer than 50 ms; more RAM won't fix that once Slimes Adventure has enough (tick lag guide). For Slimes Adventure:
- Measure first: spark's
/spark tpsand profiler work on 1.21.1 and name the mod or machine using the tick time. - Distances:
view-distance=8and a lowersimulation-distanceinserver.properties. - Pre-generate: Chunky for 1.21.1,
/chunky radius 3000then/chunky start, before people explore.
Common Slimes Adventure crashes
What a Forge and Fabric 1.21.1 server running Slimes Adventure hits most. For any other error, paste the log into the free crash log analyzer.
- Wrong Java version. Slimes Adventure on Minecraft 1.21.1 needs Java 21. Started on Java 17, it stops with
UnsupportedClassVersionError: ... class file version 65.0, this version of the Java Runtime only recognizes class file versions up to 61.0. Java version fix. - Out of memory. Slimes Adventure (125 mods on the server) needs about 4.5–5 GB for 1–3 players;
java.lang.OutOfMemoryErrormeans it ran out. Out-of-memory fix. - Client-only mod on the server. The Slimes Adventure pack file marks none of its mods client-only, so this usually means one was copied over from a player's mods folder. Check a mods list with the client-or-server-side checker. Client-only mod fix.
- After adding or updating a mod. Mods you add to Slimes Adventure by hand usually crash it with a missing dependency or a mixin conflict.
- Ticking entity or block entity. The crash report names it and gives its coordinates. Ticking entity fix.
Updates and support
Before moving Slimes Adventure past version 1.13.4, back up the world: see updating a modpack server without losing your world.
Bugs in Slimes Adventure itself go to its authors: issue tracker, wiki and Discord. Server problems on DSN: hello@dsnservers.com or Discord.
Packs like Slimes Adventure
More: all modpack guides and how to make a modded server.
Run Slimes Adventure on DSN when we relaunch.
Our pick, Premium: 8 GB, planned at $30/month.
DSN Servers isn't affiliated with Slimes Adventure or Modrinth. The pack's name, icon, summary and stats come from Modrinth's public API (checked October 4, 2026).