Ostrium OSTRIUM
VERSION 1.0.0-BETA4 · MC 1.21.11 · ALWAYS UPDATED

The Undetectable
Minecraft Client.

Ostrium is a free, next-generation utility client with 105+ modules, anti-cheat bypass, self-destruct, and a custom Sapphire GUI. Built for performance. Built to win.

▼ Download Now View 105+ Modules
105+ Modules
1.21.11 Latest MC Support
$0 Forever Free
24/7 Discord Support
2,481,302
Total Downloads
4,128
Downloads Today
1,847
Online Now
98,221
Registered Users
Security & Trust

Why does my antivirus flag Ostrium?

The injector uses process injection — the same technique some malware uses. That's why Windows Defender and other AVs sometimes flag it as "suspicious". It is 100% safe. Here's why and how to fix it.

It's a false positive.

Ostrium needs to inject the mod JAR into the running Minecraft process so the modules can hook into the game. Antivirus software sees "java.exe injecting code into another process" and triggers a generic warning — even though our code does nothing harmful.

  • No data collection — Ostrium does not phone home, does not steal tokens, does not read your browser.
  • No persistence — When you close Minecraft, Ostrium is gone. Nothing is installed to your system.
  • Open injector logic — The injector only attaches a Java agent to the Minecraft JVM. That's it.
  • Self-Destruct module — Built-in panic button wipes all traces instantly.
⚠ We recommend scanning the JARs at virustotal.com if you're unsure. The injector will show 1–4 detections out of 70+ engines — these are generic "process injector" heuristics, not confirmed malware.

How to add an exception

  1. Download the .bat + JARsGet OstriumInjector.bat, ostrium-injector.jar, and ostrium-client.jar from the download section.
  2. Open Windows SecurityStart menu → "Windows Security" → "Virus & threat protection".
  3. Manage settingsUnder "Virus & threat protection settings" click "Manage settings", then scroll to "Exclusions".
  4. Add an exclusionClick "Add or remove exclusions" → "Add an exclusion" → "Folder". Pick the folder where you saved the Ostrium files.
  5. Run OstriumInjector.batDouble-click the .bat. Java will launch the injector UI. Select your Minecraft process and click Inject.
For third-party AVs (Kaspersky, Bitdefender, Avast, etc.): look for "Exclusions", "Trusted Apps", or "Allow list" in the AV settings and add the Ostrium folder the same way.
What's inside

12+ killer features. Zero cost.

Everything a top-tier paid client offers — and more — completely free. Updated weekly.

Module Showcase

105+ modules across 7 categories

Combat, Mace, Misc, Movement, Visual, Spear, and a dedicated Cap/Cosmetics category for capes, crowns, and particles.

Head to head

Ostrium vs the competition

Ostrium wins every single row. No paid subscription, no feature gate, no bloat.

Feature OSTRIUM Prestige Vape Wurst
Get Ostrium

Download Ostrium Client

Three files. Always the latest build. Free forever. Login required to download.

v1.0.0-beta4
.bat · Launcher

OstriumInjector.bat

~1 KB · Windows
Double-click after downloading the two JARs.
v1.0.0-beta4
.jar · Mod

ostrium-client.jar

78 KB · MC 1.21.11
The actual mod with 105+ modules.
v1.0.0-beta4
.jar · Injector

ostrium-injector.jar

15 KB · Java 21+
Java agent that injects the mod into MC.
Frequently asked

Questions, answered.

Is Ostrium really free?
Yes. 100% free, no ads, no telemetry, no "premium" tier. The full client with all 105+ modules is available to everyone. We run on community donations and the Discord server.
Will I get banned for using Ostrium?
Ostrium includes anti-cheat bypass modules (NCP, Ocean, Verus, Hypixel-style) and a self-destruct panic button. That said, no client is 100% undetectable on every server — use the right config for the right server (we ship 12 premade server configs). On strictly vanilla servers, you may still be flagged by staff.
Which Minecraft versions are supported?
Ostrium currently targets Minecraft 1.21.11 (Fabric). The mod JAR is rebuilt on every Minecraft patch and uploaded to this site within hours. Bookmark this page — the files here are always the latest build.
Do I need Java installed?
Yes — Java 21 or newer. The official Minecraft launcher already ships with it. If you don't have it, install Eclipse Temurin 21 (free) from adoptium.net. The OstriumInjector.bat launcher will tell you if Java is missing.
Why does my antivirus block the injector?
It's a false positive. The injector uses Java's attach API to load the mod into Minecraft — the same technique malware uses. Check the "Why it flags" section above for step-by-step instructions to add an exception in Windows Defender, Kaspersky, Bitdefender, Avast, and others.
Can I use Ostrium on Mac or Linux?
The mod JAR works on any OS that runs Minecraft 1.21.11 with Fabric. The .bat launcher is Windows-only — Mac/Linux users can run java -jar ostrium-injector.jar directly from a terminal.
How do I open the ClickGUI?
Press RIGHT SHIFT in-game to open the custom Sapphire GUI. Press RIGHT CTRL for the panic / self-destruct keybind. All keybinds are rebindable in the Keybinds tab.
Help & Community

Need a hand? Join us.

Our Discord has 50,000+ members, dedicated support staff, and the dev team. Get setup help in minutes.

Ostrium Discord

Live support, announcements, sneak peeks, and weekly tournaments.

▶ Join the Discord
discord.gg/ostrium · 50,000+ members
Staff Only

Admin Panel

Restricted area. Requires admin credentials.