Fabric, Forge, NeoForge and Quilt — which to choose

A loader is the layer through which the game loads mods. A mod is written for a specific loader and game version, so the choice of loader determines which mods will work in your modpack.

Briefly about each

• Fabric — lightweight and quick to release for new game versions. It runs Sodium and Iris, most optimization mods, and small "vanilla+" mods.
• Forge — the oldest. Most large mods and modpacks for older versions target it — 1.7.10, 1.12.2, 1.16.5, 1.20.1.
• NeoForge — a fork of Forge. Since 1.20.2, many large mods have moved to it from Forge. On 1.20.1, NeoForge accepts most Forge mods; on newer versions, Forge and NeoForge mods are not interchangeable.
• Quilt — a fork of Fabric. It runs most Fabric mods, but has few mods of its own.

Which one to choose

1. You play on a server — use the same loader and version as the server. The easiest way is to join from the server catalog: the launcher will pick the modpack for you.
2. You need a specific mod — check its catalog page to see which loaders and versions it supports, and create a modpack for them. The “New modpack” button on the mod's page will do it for you.
3. You want FPS, shaders, and a few handy mods — Fabric.
4. A large modded modpack — use the loader it was released for. Ready-made modpacks from the catalog install with the right loader automatically.

Without a loader (“Vanilla”), you can't install mods, FPS-boosting mods, or Millida cosmetics — the launcher will warn you about this when creating a modpack.

Where to choose or change the loader

• New modpack: “New modpack” → the “Loader” and “Loader version” fields. If you're unsure about the version, leave “Recommended”.
• Existing modpack: open the modpack → “Settings” → “Version and loader” → “Change” → select a loader → “Change”.

After changing the loader, the launcher will tell you how many mods are in the modpack — check them: mods from the previous loader won't work in the new one. It's usually easier to create a new modpack.

Why a mod doesn't see the loader or won't launch

• The mod is for a different loader. A Forge mod in a Fabric modpack (or vice versa) simply won't load. The crash window will say “The mods folder contains a mod for a different loader”. Install the mod version for your modpack's loader.
• Fabric API is missing. Almost all Fabric mods need it. When installing from the catalog, it's added automatically; if the mod was added as a file, click “Install dependencies” in the crash window.
• The loader is older than the mod requires. The crash window will have an “Update loader” button — the game version doesn't change.
• The mod is for a different game version. The loader is right, but the version isn't — the mod won't load or the game will crash. Install the mod version for your game version.
• A Fabric mod in a Quilt modpack. Most work, but not all. If this particular mod doesn't work, create a Fabric modpack.

Error messages and buttons are covered in the article Minecraft crash codes and messages. For installing mods, see How to install mods, shaders, resource packs, and modpacks.

Loader on your own server

The same rules apply to a server: the loader and version must match between players and the server. More for owners: Fabric server, Forge server, NeoForge, Quilt.