librime is the core library of the Rime Input Method Engine, a modular, cross-platform C++ framework for building Chinese and East Asian input methods. It provides a flexible pipeline architecture composed of processors, segmentors, translators, and filters, all configurable via YAML schemas. The library handles dictionary compilation from text to binary trie formats (leveldb and marisa-trie), spelling algebra for variant syllable mapping, and user-specific adaptation through frequency and custom phrase databases. It exposes a stable C API for integration into frontends (e.g., IBus, Squirrel, Weasel) and supports dynamic plugin loading for extensibility. The codebase is well-structured with clear separation of concerns, a component registry pattern, and extensive unit tests. Notable technical strengths include a custom double-array trie implementation (darts-clone), a sophisticated YAML config compiler supporting inheritance and patching, and an event-driven context system for real-time composition state.