RetroAPI

RetroAPI is a content-registration library for Minecraft Beta 1.7.3 that lets mods add blocks, items, recipes, entities, dimensions and more without requiring StationAPI. It runs on Ornithe (Fabric Loader + OSL) and Babric, and transparently delegates to StationAPI when that mod is also installed.

Developer Portal

To start developing for b1.7.3 with it go here!
https://matthewperiut.github.io/retroapi/index.html

What it implements

Registration

Custom blocks and items with automatic, stable ID assignment - block IDs are expanded well past the vanilla 256 cap, and assignments persist across loads.
Block entities without subclassing BlockWithBlockEntity (RetroBlockEntityType).
Inventory / menu GUIs (chest, furnace and dispenser styles) with automatic slot sync (@SyncField).
Crafting, smelting and furnace-fuel recipes (RetroRecipes).
Custom entities with renderers, and custom dimensions reached through walk-in portal blocks.
Achievements and achievement pages.
Sound autoloading and automatic lang / translation generation.

Rendering

Expanded texture atlas plus custom block and item renderers and render types.

Vanilla-safe world storage (sidecar system)

All modded content is written to retroapi/ sidecar files keyed by string identifiers, so a world can be opened in vanilla without crashing or losing data and reopened in RetroAPI intact.
Covers extended block IDs, modded block entities, modded items inside vanilla containers, and dropped item entities.

Multiplayer

OSL-based networking with server-to-client ID mapping sync and extended-block chunk sync.

StationAPI compatibility (optional, bundled)

Ships a retroapi-stationapi companion that loads only when StationAPI is also present and delegates registration, rendering, dimensions and world conversion to StationAPI. With it, RetroAPI worlds round-trip through StationAPI's flattened world format without data loss.

Both jars include the StationAPI compatibility layer; it activates automatically if StationAPI is installed and stays dormant otherwise.