EternalExchange

Equivalent-exchange alchemy for Fabric. Learn items, burn them into EMC, and transmute the world back out of it — on Minecraft 1.21.1.

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EternalExchange is a standalone Fabric mod built around one idea: everything has a value. Every item in the game gets an EMC (Energy-Matter Covalence) value computed from its recipes at world load. Anything you've learned can be broken down into EMC and reshaped into anything else you know — if you can afford it.

Features

• The EMC engine — item values solved from the full recipe graph at world load (~1,500 values on a vanilla instance; mods that add recipes are priced automatically)
• Transmutation Table & Tablet — learn items permanently, burn matter into EMC, withdraw anything you know
• Automation chain — Energy Collectors (MK1–3) generate EMC from light, Antimatter Relays (MK1–3) buffer and boost it, Energy Condensers duplicate any learned item from raw EMC
• Dark & Red Matter progression — tools, weapons, and armor with charge levels, modes, and area abilities; Dark and Red Matter Furnaces; item-holding Pedestals with ambient powers
• The Gem armor set — flight, damage absorption, offensive abilities, all toggleable with keybinds
• Rings, amulets, and stones — creative-flight rings, infinite water/lava amulets, a world-transmuting Philosopher's Stone with live preview overlay, healing/feeding stones, and more
• Alchemical Bags & Chests — 104-slot color-coded bags that live on your player, with item-suction and auto-repair companions
• Klein Stars & alchemical fuels — portable EMC batteries and a three-tier fuel line that burns in any furnace
• Fully data-driven — override any value with custom_emc.json or datapack conversion files; tweak everything in config/ProjectE/*.toml

Installation

Requirements: Minecraft 1.21.1, Fabric Loader, Fabric API for 1.21.1.

1. Install Fabric Loader for 1.21.1.
2. Drop EternalExchange-<version>.jar (from Releases) and Fabric API into mods/.
3. For servers, place the same two jars in the server's mods/ directory.

Roadmap

The core loop is complete and playable. Planned work:

• Recipe viewer integration (EMI/REI) with transmutation support
• Trinkets support for rings and amulets
• Fabric transfer-API bridges (machines as pipe targets, amulets filling tanks)
• Server→client config sync for multiplayer consistency
• Original content beyond the classic equivalent-exchange set

Building from source

git clone https://github.com/sidebandstudio/EternalExchange.git
cd EternalExchange
./gradlew build        # requires JDK 21

The jar lands in build/libs/. ./gradlew runClient / runServer launch a dev instance.

Contributing

Bug reports and pull requests are welcome. See CONTRIBUTING.md for guidelines — clear reproduction steps make reports actionable.

Origins & License

EternalExchange began as an independent Fabric port of the MIT-licensed ProjectE (itself a rewrite of Equivalent Exchange 2), and it retains compatibility with that mod's data formats — worlds, configs, and datapacks carry over. Full credit to those projects' authors for the original design; see LICENSE for notices.

EternalExchange is not affiliated with, maintained by, or endorsed by the ProjectE team. It is developed independently and follows its own direction — report issues here, never upstream.

Licensed under the MIT License. Not affiliated with Mojang or Microsoft.