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Loaders and Minecraft versions

Every Minecraft mod is built for a specific loader and a specific game version. The loader is the framework that lets your mod hook into the game (Fabric, Forge, and NeoForge each do this a different way), and the version is the Minecraft release the mod expects to run on. Pick the wrong pair and the file will not load. In Orca you set both before the build, and the AI compiles, boots a real test server, and confirms the jar actually loads on that loader and version before it hands you the file.

Orca builds for current versions first (1.21, 1.20) and reaches back to 1.12.2 when you name the version in your request. If you do not name one, you get a recent default. When you do name one, for example "make this for 1.21.4," the AI targets that exact release. This page covers how to choose a loader, how to set a version, and the one honest caveat about Quilt.

Which loader to pick

Orca builds mods for three loaders. They are not interchangeable, so the jar you get is tied to the loader you choose. If you are not sure, Fabric vs Forge walks through the trade-offs in plain terms.

A quick way to decide:

  • Fabric: lightweight and fast to update to new Minecraft versions. A good default for a single mod or a small set of mods on a current release.
  • Forge: the long-standing loader with the largest back catalog of older mods. Pick it when you want compatibility with an existing Forge pack or an older version.
  • NeoForge: the actively maintained fork of Forge for recent versions. Pick it for new builds on 1.20.1 and up where you want the Forge-style API without the legacy baggage.

How versions work

Orca targets current versions first and supports older ones down to 1.12.2. The simplest way to lock a version is to say it in your request.

Name the version in plain English and the AI builds for it:

  • "make this for 1.21.4" targets that exact release
  • "build a Fabric mod for 1.20.1" sets the loader and the version together
  • Leave the version out and you get a recent default
  • Type your own version if the one you want is not in the list, all the way back to 1.12.2

Matching the loader, version, and server

Three things have to agree: the loader, the Minecraft version, and the place you run the mod. A 1.21 Fabric mod will not load on a 1.20 Forge server. When you create an Orca server you pick the same loader and version, so a Fabric server runs your Fabric mods and a Forge server runs your Forge mods.

If you plan to host the creation, set up the server to match before you join. See hosting for creating a Java server on Vanilla, Paper, Purpur, Spigot, Bukkit, Folia, Forge, Fabric, or NeoForge, and how to install a mod for getting the file onto it.

A note on Quilt

Orca does not build for Quilt and does not boot a Quilt test server, so there is no Quilt build or one-click test path here. What is true: Quilt is built to run Fabric mods, so a Fabric mod you make in Orca will generally load on a Quilt setup, and you can publish a Fabric creation as Quilt-compatible. Treat Quilt as a runtime your Fabric build happens to work on, not a build target you select in Orca.

If Quilt is a hard requirement for your project, build for Fabric and run that jar on Quilt yourself.

Editing the version of an existing mod

You can change the target on your own creations and ask the AI to rebuild. Open the project, say which loader or version you want, and it recompiles and re-runs the load test against the new target.

The same applies to uploaded files you own and to third-party mods where the license allows editing. Upload a .jar up to 100 MB, pick the loader and version, and remix it. See edit a mod with AI for how the workspace handles this.

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