Best Whisper Alternatives

Cactus is a YC-backed low-latency AI engine for mobile and wearable devices that runs LLMs, transcription, embedding, and TTS models locally. It achieves 16-20 tok/sec on older devices and 70+ tok/sec on flagships with ARM SIMD kernels optimized for Snapdragon, Apple, and MediaTek processors. Supports Qwen, Gemma, Llama, DeepSeek with Flutter, React Native, and Kotlin SDKs.

BitNet is Microsoft's official inference framework for 1-bit quantized large language models that enables running models with up to 100 billion parameters on standard consumer CPUs without requiring a GPU. By leveraging extreme quantization where weights use only 1.58 bits on average, BitNet achieves dramatic reductions in memory footprint and computational cost while maintaining competitive output quality for many practical use cases.

Deepgram is a voice AI infrastructure platform providing low-latency speech-to-text, text-to-speech, and conversational AI APIs. Its Nova-3 model delivers industry-leading accuracy for real-time transcription with streaming support, interruption handling, and multi-language capabilities. Used by 1,300+ organizations including Twilio and Vapi, Deepgram powers voice features in applications ranging from call centers to AI agent voice interfaces.

PersonaPlex is NVIDIA's open-source, full-duplex speech-to-speech conversational AI model that enables persona control through text-based role prompts and audio-based voice conditioning. Built on the Moshi architecture, it produces natural, low-latency spoken interactions with consistent persona across conversations. The model supports multiple pre-packaged voice embeddings for both natural and varied speaking styles, making it suitable for building interactive voice agents and assistants.

Vosk is an offline speech recognition toolkit supporting 20+ languages with compact 50MB models that run on Raspberry Pi, Android, iOS, and servers. It provides streaming API with zero-latency response, speaker identification, and reconfigurable vocabulary. Vosk offers bindings for Python, Java, Node.js, C#, Go, and Rust. Unlike cloud-based alternatives, all processing happens locally with no internet required. Apache 2.0 licensed with 14K+ GitHub stars.