Voice Models Catalog

Xantly exposes 33 voice models across 6 providers. Use the stt_model / tts_model parameters on the voice endpoints to pick a specific model, or let Xantly auto-route based on language and latency budget.

All models route through the same API key as chat, there is no separate voice subscription. Voice usage bills per-minute (provider pass-through) plus a per-minute platform fee. See voice-agents guide for the billing breakdown.

Speech-to-Text (STT), 10 models

Use with POST /v1/voice/transcribe or as stt_model on POST /v1/voice/chat.

Text-to-Speech (TTS), 13 models

Use with POST /v1/voice/synthesize or as tts_model on POST /v1/voice/chat.

Realtime (bidirectional audio), 3 models

Use with GET /v1/voice/realtime (WebSocket upgrade).

Audio LLMs, 7 models

Text + audio input, text + audio output. Use via POST /v1/chat/completions with audio content parts, or via the voice endpoints.

Music Generation, 2 models

Text → audio (music). Use via POST /v1/chat/completions with the model slug.

Speech-to-Speech, 1 model

Audio → audio transformation (voice conversion).

Auto-routing defaults

If you omit stt_model / tts_model, Xantly auto-routes:

• STT: English → deepgram/nova-2, other languages → openai/whisper-1
• TTS: openai/gpt-4o-mini-tts by default, or ElevenLabs/Deepgram/Groq when provider is set on the request

Key rotation and fallback

All models that go through OpenRouter, NVIDIA, or Groq use round-robin key rotation across your configured API key pool (e.g. GROQ_API_KEY_1..6). On a per-key 402 / 429, requests automatically waterfall to the next key in the pool. See reliability guide for details.

Usage example

# Transcribe with Groq Whisper (cheapest STT)
curl -X POST https://api.xantly.com/v1/voice/transcribe \
  -H "Authorization: Bearer $XANTLY_API_KEY" \
  -F "[email protected]" \
  -F "stt_model=groq/whisper-large-v3-turbo"

# Synthesize with ElevenLabs Flash (low-latency TTS)
curl -X POST https://api.xantly.com/v1/voice/synthesize \
  -H "Authorization: Bearer $XANTLY_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "text": "Hello from Xantly",
    "model": "elevenlabs/eleven_flash_v2_5",
    "voice": "21m00Tcm4TlvDq8ikWAM",
    "output_format": "pcm_16000"
  }' --output hello.pcm

# Full pipeline with explicit STT + TTS picks
curl -X POST https://api.xantly.com/v1/voice/chat \
  -H "Authorization: Bearer $XANTLY_API_KEY" \
  -F "[email protected]" \
  -F "stt_model=groq/whisper-large-v3-turbo" \
  -F "tts_model=deepgram/aura-2"