Zyphra Releases ZONOS3-Mini: Open-Source TTS With 100M Active Parameters

Zyphra has released ZONOS3-Mini, an Apache 2.0 text-to-speech model that is a sparse Mixture of Experts with 800M total and about 100M active parameters, supporting zero-shot voice cloning and word-level delivery control. It runs via WebGPU in the browser, MLX on Apple Silicon, ggml on CPU/CUDA/Metal/Vulkan, and SGLang-Omni on NVIDIA GPUs, with Zyphra reporting 80 ms median time to first audio on one H100 at 8 concurrent requests. Zyphra reports it ranks first among open models on its self-run ZTTS2-Eval Capability Index at 66.2 in speaker-embedding mode, while reference-clip mode scores only 44.7.