Gradium TTS
Paris-based voice platform (reported as a Kyutai spin-out) with bidirectional WebSocket TTS/STT in English, French, German, Spanish and Portuguese, credit-based plans.
Overview
Best for: European-language agents wanting a Kyutai-lineage streaming model.
At a glance
Public beta. ~200 ms first audio (vendor), vendor-reported Coval P50 158 ms. Price is the XS plan effective rate ($13 for 225K credits); L plan about $36/1M. Concurrency 5 on XS (Free 2). Free plan 45K credits, non-commercial.
Text
Not verified
English, French, German, Spanish, Portuguese (AWS Marketplace listing)
Not verified
Vendor: ~200 ms first audio; vendor-reported Coval P50 TTFA 158 ms.
Not verified (AWS Marketplace listing exists)
Not verified.
Features
- bidirectional WebSocket
- multiplexing
Pricing
| What | Price | Unit |
|---|---|---|
| Free | $0 | monthly |
| XS | $13/month | monthly |
| S | $43/month | monthly |
| M | $340/month | monthly |
| L | $1,615/month | monthly |
| TTS credit rate | 1 credit | per character |
900 chars/min; L plan ~$35.9/1M vs XS ~$57.8/1M
Free tier: 45K credits/month, non-commercial
Source: gradium.ai
Setup
- Sign up at gradium.ai and create an API key.
- Follow docs.gradium.ai for the WebSocket TTS protocol.
Endpoint
See https://docs.gradium.aiAuthentication
API key
Warnings
Free tier is non-commercial
The Free plan explicitly excludes commercial use.
Expensive per character at small plans
XS works out to ~$58 per 1M characters, several times Deepgram or Inworld.
Public beta
The site banner describes the new TTS model as public beta; expect changes.
Plus 12 warnings that apply to all text-to-speech, streaming APIs. See category warnings.
Limits
- TTS concurrency: Free 2, XS/S 5, M 10, L 15
Models and products
| Name | Status |
|---|---|
| Gradium TTS | Public beta (per site banner) |
Docs and sources
Docs
Sources used
- gradium.ai/pricing
- aws.amazon.com/marketplace/pp/prodview-jjbvzxqmhrdiw
- gradium.ai/content/how-to-choose-a-tts-api
Endpoint URLs, audio formats, Kyutai relationship, latency.