RealtimeSTT is a production-grade real-time speech-to-text library and server. The core library provides `AudioToTextRecorder`, a facade that orchestrates microphone capture, voice activity detection (VAD), wake-word detection, and multiple ASR backends (faster-whisper, sherpa-onnx, whisper.cpp, etc.) for low-latency realtime and final transcription. It features a dual-lane architecture combining an ultrafast speculative model with a slower accurate model, merged via a sticky alignment algorithm, and a text stabilizer that commits only evidence-backed partials. The server component (`stt-server-production`) is a FastAPI/WebSocket application with a versioned protocol (`realtimestt.remote.v1`) supporting per-session ordered event delivery, fair inference queues, preview snapshots, resume, and HTTP transcription. External dependencies include PyTorch, torchaudio, faster-whisper, sherpa-onnx, and optional engines. The system is designed for voice assistants, dictation, and multi-user ASR services.