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SecondBrainMinecraft mod for 1.21.11

AI-powered NPCs that chat and play like real players

server onlynewest supported 1.21.11TechnologyAdventureCursedSocial
Latest version
3.1.7
Minecraft
1.20.1 to 1.21.11
Java
Java 21+
Loader
Fabric
Licence
LGPL-3.0-only
Downloads
25.1k
Updated
5 mo ago
Available on
Modrinth
Space NodeOur hosting

Host SecondBrain servers

One click and SecondBrain is installed with the right loader, on hardware built for it.

  • 1.21.11
  • Fabric
  • One click mod install
  • Loader matched for you
  • Ryzen CPUs
  • NVMe SSD
Deploy a serverFrom €0.90 per GB

Screenshots

Click a screenshot to open it. Screenshots are served from the author’s own host and belong to them.

Minecraft versions

Every version SecondBrain declares support for, newest first, with the Java runtime that version needs.

Other mods
MinecraftThroughJavaEvidenceReleased
1.21.11Fabric21+declared9 Dec 2025
1.21.10Fabric21+declared7 Oct 2025
1.21.8Fabric21+declared17 Jul 2025
1.21.3Fabric21+declared23 Oct 2024
1.21.1Fabric21+declared8 Aug 2024
1.20.4Fabric17+declared7 Dec 2023
1.20.3Fabric17+declared4 Dec 2023
1.20.1Fabric17+declared12 Jun 2023

Download

From SecondBrain’s own host. Nothing is re-hosted here.

3.1.7alpha18 Apr 2026

secondbrain-1.20.1-v3.1.7-alpha.jar · 30.4 MB · for 1.20.1

Download latest
d0ec30a949da…
Older versions21
  • 3.1.625 Mar 20261.21.1131.7 MB771 downloads61b87a5e9131…Get
  • 3.1.56 Dec 20251.21.830.6 MB1.4k downloads8f1c5930f4f5…Get
  • 3.1.423 Nov 20251.21.830.6 MB199 downloads7949b87b3c12…Get
  • 3.1.216 Nov 20251.21.830.6 MB127 downloadscce241410e19…Get
  • 3.1.115 Nov 20251.21.830.6 MB60 downloadsc44385d24cc2…Get
  • 3.0.126 Oct 20251.21.830.6 MB277 downloadsdd06f4bc6857…Get
  • 3.0.025 Oct 20251.21.830.6 MB204 downloadsb9d9b915055b…Get
  • 2.1.25 Jul 20251.21.130.1 MB1.6k downloadseeaf31ce627a…Get
  • 2.1.130 May 20251.21.119.7 MB799 downloads7a7aa57be6fb…Get
  • 2.1.028 May 20251.21.119.7 MB132 downloads0e260d25c7f5…Get
  • 2.0.33 May 20251.21.119.7 MB297 downloads535877297657…Get
  • 2.0.224 Apr 20251.21.119.7 MB116 downloadsa121eb478322…Get
  • 2.0.124 Apr 20251.21.118.9 MB67 downloadsf3a170189be7…Get
  • 1.0.928 Dec 20241.20.47.9 MB1.2k downloadsc28ff2fc018b…Get
  • 1.0.8-beta28 Dec 20241.20.47.9 MB1.0k downloads5a11fe620dd3…Get
  • 1.0.7-beta15 Dec 20241.20.410.0 MB168 downloadsab91c2de6ef8…Get
  • 1.0.6-beta11 Dec 20241.20.4, 1.20.310.0 MB100 downloads9b77810003b3…Get
  • 1.0.5-beta16 Nov 20241.20.47.9 MB400 downloads5529e1a4529a…Get
  • 1.0.4-beta14 Nov 20241.20.47.9 MB115 downloadsed1401914af0…Get
  • 1.0.3-alpha12 Nov 20241.20.47.9 MB108 downloadse0e490bf509c…Get
  • 1.0.1-alpha8 Nov 20241.20.47.9 MB98 downloadsc4ab2cbeea80…Get

Frequently asked

Does SecondBrain work on Minecraft 1.21.11?

Yes. 1.21.11 is the newest Minecraft version SecondBrain declares support for, and the claim comes from the author's own release metadata rather than from a compatibility list somebody maintains by hand.

Which Minecraft versions does SecondBrain support?

Everything the author has declared, from 1.20.1 up to 1.21.11. The full list is in the table above, with the Java runtime each version needs next to it.

Do I need to install SecondBrain on the client or the server?

The server only. Players join with an ordinary Minecraft client and install nothing.

Which platform or loader does SecondBrain support?

Fabric. A build for one platform or loader will not necessarily load on another, so this is the first thing to check before the Minecraft version.

Which Java version do I need for SecondBrain?

On the newest Minecraft version it supports, Java 21 or newer. The requirement comes from the Minecraft version you run rather than from the mod itself, so on an older supported Minecraft the answer is that version's Java, not this one.

What licence is SecondBrain under?

LGPL-3.0-only, as stated by the author on the platform we synced it from. Check the project's own page before redistributing or bundling it.

How do I install SecondBrain?

Install the matching loader first, then put the downloaded file in your mods folder and start the game. The loader, the mod and Minecraft all have to be on the same version, which is the usual reason a mod does not appear in game.

Where do I download SecondBrain safely?

Start with the author's page on Modrinth, which is where the data here is synced from. MCReference does not host or repackage files. The download link goes to the source recorded for that release; verify the publisher, filename and checksum before running it.

Works on the same versions

Ordered by how much of the recent Minecraft version coverage overlaps, not by popularity.

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Last checked 2 mo ago against Modrinth. We do not host files and we do not republish descriptions; every download link points at the author’s own release.

Is this information wrong or missing something? .