How do I run a custom or unlisted JAR (Waterfall, Velocity, Magma, a specific fork)? — Minecraft

Q: Where do I put the JAR?

In the server root, alongside server.properties, via the Files manager.

Q: Do I have to rename it to server.jar?

Either rename it to server.jar, or point the SERVER JAR FILE variable in the Startup tab at your file.

How do I run a custom or unlisted JAR (Waterfall, Velocity, Magma, a specific fork)?

If the software or build you want isn't in the Versions catalog — a specific proxy like Waterfall or Velocity, a hybrid like Magma, or a particular fork — you can install it manually. It's a straightforward file-and-startup job.

Installing a custom JAR

Download the .jar from the official source.
Open Files and upload it to the server root (where server.properties lives).
Rename it to exactly server.jar — our startup script looks for that name — or set the JAR name in the Startup tab's SERVER JAR FILE variable.
Start from the Console.

Proxies and custom flags

For proxies (Velocity/Waterfall) the same steps apply. You may also want custom startup flags for these.

Tip: For proxies you'll often want custom startup flags — see the startup-command answer for how to set them.

Frequently asked questions

Where do I put the JAR? In the server root, alongside server.properties, via the Files manager.

Do I have to rename it to server.jar? Either rename it to server.jar, or point the SERVER JAR FILE variable in the Startup tab at your file.