Audio

26 audio aliases · TTS (Kokoro / Chatterbox / VibeVoice / VoxCPM / Dia) + STT (Whisper / Parakeet).

rapid-mlx serves OpenAI-compatible /v1/audio/transcriptions and /v1/audio/speech endpoints — drop-in for any OpenAI SDK client. 26 aliases ship today across two modalities: text-to-speech (Kokoro, Chatterbox, VibeVoice, VoxCPM, Dia) and speech-to-text (Whisper, Parakeet). All aliases route through the same mlx_audio-backed runtime so swapping models is one CLI flag.

family

Audio

aliases

26

lines

7

install

rapid-mlx serve <alias>

OpenAI base URL

http://localhost:8000/v1

Usage

The audio aliases route through OpenAI-compatible endpoints — any OpenAI SDK works without per-model config.

# Text-to-speech
curl -X POST http://localhost:8000/v1/audio/speech \
  -H "Content-Type: application/json" \
  -d '{"model": "kokoro", "input": "hello from rapid-mlx"}' \
  --output hello.wav

# Speech-to-text (multipart upload)
curl -X POST http://localhost:8000/v1/audio/transcriptions \
  -H "Content-Type: multipart/form-data" \
  -F file=@hello.wav \
  -F model=whisper-large-v3-turbo

Lines in this family

• Text-to-speech (TTS) · Kokoro · Chatterbox · VibeVoice · VoxCPM · Dia
• Speech-to-text (STT) · Whisper · Parakeet

Text-to-speech (TTS) · 13 aliases

OpenAI-compat endpoint: POST /v1/audio/speech. Pass model (any alias from the tables below), input (the text to synthesise), and optionally voice (per-family voice id — falls back to the alias's default voice when omitted).

Kokoro · 7 aliases

Lightweight 82M open-weights TTS — the default rapid-mlx TTS pick. Three quants (bf16 / 8-bit / 4-bit) with short- and long-form aliases for each.

Chatterbox · 2 aliases

Multilingual expressive TTS with voice cloning via reference audio. Both fp16 and 4-bit ship.

VibeVoice · 2 aliases

Realtime low-latency 0.5B TTS. Per-language voice caches; en-Grace_woman is the canonical English-female default.

VoxCPM · 1 alias

Chinese/English high-quality TTS, CPM-based. Single alias.

Dia · 1 alias

Multi-speaker dialogue TTS in 4-bit. Best-effort — covered by the probe but mlx_audio support is experimental.

Speech-to-text (STT) · 13 aliases

OpenAI-compat endpoint: POST /v1/audio/transcriptions. Send multipart/form-data with file (the audio bytes) and model (any alias from the tables below). Optional language hint accepted by Whisper aliases.

Whisper · 8 aliases

OpenAI's multilingual STT family — tiny → large-v3 + large-v3-turbo. whisper-1 is wired as an OpenAI-compat placeholder pointing at large-v3.

Parakeet · 5 aliases

NVIDIA Parakeet TDT 0.6B — English-only but fastest STT in the registry. v2 and v3 checkpoints ship.

Notes & caveats

• TTS aliases default to a sensible per-family voice but accept any voice supported by the underlying model — pass voice in the JSON body of /v1/audio/speech.
• STT aliases accept both multipart/form-data audio uploads and the OpenAI-style file field on /v1/audio/transcriptions.
• whisper-1 is wired as an OpenAI-compat placeholder — it resolves to whisper-large-v3 so legacy OpenAI client code works unchanged.
• Dia 1.6B is best-effort — covered by the audio probe but mlx_audio support is experimental upstream; report bugs upstream if synth fails.

External reading

• Kokoro 82M on HF
• Whisper large-v3 (MLX) on HF
• Parakeet TDT 0.6B v2 (MLX) on HF

Where next