JustEnoughItems (JEI) is a Minecraft mod that provides an in-game recipe viewer and ingredient browser. It is a client-side mod that integrates with both Fabric and NeoForge mod loaders via a common core library. The system's primary function is to display all available recipes, items, and fluids in a searchable overlay, allowing players to look up crafting, smelting, brewing, and other recipes. It also supports a plugin API (IModPlugin) that lets other mods register custom recipe categories, ingredient types, recipe transfer handlers, GUI handlers, and search prefixes. The codebase is organized into distinct modules: Common (shared logic, networking, configuration, and platform abstractions), Library (core implementations for recipe management, ingredient indexing, vanilla integrations, and runtime), Gui (client-side overlays, input handling, bookmarking, and search), and platform-specific modules for Fabric and NeoForge. The mod includes a sophisticated search engine with prefix-based tokens, an ingredient filter, a configurable overlay layout, ghost ingredient dragging, and a bookmark system. Recipe transfer to in-game crafting grids is handled via network packets with server-side permission checks. The codebase demonstrates strong architectural practices with clear API separation, extensive unit and game tests, and a flexible configuration framework. However, it exhibits significant platform duplication between Fabric and NeoForge implementations and carries deprecated API surfaces, indicating ongoing evolution.