Prices are per million input characters. Speed is the median over real ModelRelay requests, in characters synthesized per second. Voice quality is the Artificial Analysis TTS arena Elo, from blind listener votes. Models are listed rather than ranked until there are enough of them to compare.
| Model | Price | Speed chars/s, ModelRelay median | Voice quality AA arena Elo |
|---|---|---|---|
| Gemini 3.8 Flash TTS | $16.50/1M characters billed per input character | 28 chars/s | 1268 ±16 |
Use ModelRelay's Responses API directly, or point an existing OpenAI or Anthropic SDK at the compatible endpoints.
128 successful streams measured · 30m window
curl https://api.modelrelay.ai/api/v1/responses \
-H "Authorization: Bearer $MODELRELAY_API_KEY" \
-H "Content-Type: application/json" \
-d '{"model":"claude-sonnet-5","input":"Hello"}'Change the model. Keep everything else.
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