// modpack server guide
Cobblemon Delta server hosting & setup guide
A Cobblemon Delta server needs Java 21 and about 2.5–4 GB of RAM for up to 15 players.
Pokemon Cobblemon Pack - QoL and Performance mods! The server included in the pack has Mega Evolution, Paradox Pokemon, Area Zero, Real Player Gyms, Raids, Dungeons, Pokemon Fishing!
Summary from Cobblemon Delta on Modrinth.
Cobblemon Delta is a Fabric modpack for Minecraft 1.21.1 (older versions go back to 1.20.1) with 56 mods, 29 of which run on the server. We'd pick our Standard plan (4 GB) for it.
Quick facts
| Loader | Fabric |
|---|---|
| Minecraft versions | 1.21.1, 1.20.1 |
| Java needed | Java 21 for Minecraft 1.21.1Older pack versions: Java 17 for 1.20.1. Java version chart. |
| Mods | 29 run on the server56 in the pack. The other 27 are client-only, and the server skips them. |
| RAM | About 2 GB for 1–3 playersBy player count. |
| Downloads | 1,638,467 on Modrinth |
| Last updated | October 1, 2026 (version 4.2.0) |
| First published | October 16, 2023 on Modrinth |
| Server support | Supported: it runs on a server, and works in single player too. |
| Server pack | Not published separatelyHow to build the server. |
| Modrinth tags | adventure, lightweight, optimization, quests |
Cobblemon Delta server files
No. Cobblemon Delta 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 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 Cobblemon Delta server need?
| Players online | RAM | DSN plan |
|---|---|---|
| 1–3 players | About 2 GB | Standard (4 GB) |
| 4–8 players | About 2–3 GB | Standard (4 GB) |
| 9–15 players | About 2.5–4 GB | Standard (4 GB) |
Estimated from 29 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 -Xmx3500M on 4 GB. Fabric 1.21.1 takes it in the java command (-Xmx), usually in the start script. RAM guide.
Cobblemon Delta server requirements
| Java | Java 21 |
|---|---|
| Loader | Fabric for Minecraft 1.21.1 |
| CPU | Fast single-core speed (one main thread). |
| RAM | About 2–4 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 Cobblemon Delta
Standard
4 GB RAM · planned launch price $16/month
At about 29 Fabric mods this is a light pack, so 4 GB of RAM covers it for a small group.
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 Standard servers open.
More than 15 players, or lots exploring at once? Go up to Premium (8 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 Cobblemon Delta server on your own PC
What's specific to Cobblemon Delta, 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
java -jaron the Fabric 1.21.1 server launcher, 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 Cobblemon Delta on DSN
Once we relaunch (join the launch list), on DSN you'd install Cobblemon Delta from the panel's Modrinth modpack installer (version 4.2.0), pick Java 21 on the Startup tab and accept the EULA in the console. No port forwarding.
How to play Cobblemon Delta with friends
Each player installs Cobblemon Delta version 4.2.0 with the Modrinth App or Prism Launcher, the same version as the server, and adds the server's address under Multiplayer.
Different versions of Cobblemon Delta 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 Cobblemon Delta
Can't keep up! Is the server overloaded? means ticks take longer than 50 ms; more RAM won't fix that once Cobblemon Delta has enough (tick lag guide). For Cobblemon Delta:
- 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 Cobblemon Delta crashes
What a Fabric 1.21.1 server running Cobblemon Delta hits most. For any other error, paste the log into the free crash log analyzer.
- Wrong Java version. Cobblemon Delta 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. Cobblemon Delta (29 mods on the server) needs about 2 GB for 1–3 players;
java.lang.OutOfMemoryErrormeans it ran out. Out-of-memory fix. - Client-only mod on the server. Cobblemon Delta includes 27 client-only mods, which a server install skips; copying a player's mods folder brings them back and stops the server. 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 Cobblemon Delta 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 Cobblemon Delta past version 4.2.0, back up the world: see updating a modpack server without losing your world.
Bugs in Cobblemon Delta itself go to its authors: Discord. Server problems on DSN: hello@dsnservers.com or Discord.
Packs like Cobblemon Delta
More: Cobblemon server hosting, all modpack guides and how to make a modded server.
Run Cobblemon Delta on DSN when we relaunch.
Our pick, Standard: 4 GB, planned at $16/month.
DSN Servers isn't affiliated with Cobblemon Delta or Modrinth. The pack's name, icon, summary and stats come from Modrinth's public API (checked October 4, 2026).