# Gradium Review

> Gradium review: Real-time voice-agent infrastructure play: WebSocket-first streaming TTS in 5 European languages with instant cloning, on-device models.

![Gradium logo](https://www.versusref.com/logos/gradium.png)

Real-time voice-agent infrastructure play: WebSocket-first streaming TTS in 5 European languages with instant cloning, on-device models (Phonon), and credit-based pricing. Active and well-funded (site announced funding extension to $100M, July 2026).

Among the 15 text-to-speech tools we track, Gradium has the 10th-largest voice library.

From $13/mo · facts verified Jul 20, 2026

## What we know about Gradium

This is our verified profile of Gradium, a text-to-speech apis platform - real-time voice-agent infrastructure play: WebSocket-first streaming TTS in 5 European languages with instant cloning, on-device models (Phonon), and credit-based pricing. Active and well-funded (site announced funding extension to $100M, July 2026). Every fact about Gradium below carries the source it came from and the day we checked it.

On pricing, Gradium starts at $13 per month for its entry tier. That is the sticker rate: real production cost usually runs higher once you add a language model, a voice provider, and telephony minutes.

On capabilities, Gradium covers streaming audio output, realtime websocket api, instant voice cloning, professional voice cloning, ssml support, and word-level timestamps, and does not offer commercial use on free tier. Each of those is verified against Gradium's own docs or dashboard, not marketing copy.

Among the 15 text-to-speech tools in our matrix, Gradium leads with the 10th-largest voice library and lags at the 36th-widest language coverage; the fact sheet below has the raw numbers behind that placement.

In total we track 21 verified facts for Gradium today, each linking the primary source it came from so you can check our work - and vendor claims we have not measured ourselves are labeled as such on the Gradium fact sheet below.

## Gradium pricing

Cheapest paid plan $13/mo with 225,000 characters included, verified Jul 20, 2026 ([source](https://gradium.ai/pricing)).

| Monthly volume | $ / 1M chars | $ / audio-min | Monthly bill |
| --- | --- | --- | --- |
| 200K chars/mo | $65 | $0.0618 | $13 |
| 2M chars/mo | Higher plan | Higher plan | Higher plan |
| 20M chars/mo | Higher plan | Higher plan | Higher plan |

Effective rates from published pricing; subscription plans resolve to plan fee plus overage. ~950 characters ≈ 1 audio minute.

## Fact sheet

### Pricing

| Fact | Value | Verified | Source |
| --- | --- | --- | --- |
| Pricing model | Monthly subscription credit plans: Free $0 (45k credits) | Jul 20 | [source](https://gradium.ai/pricing) |
| Cheapest paid plan | $13 | Jul 20 | [source](https://gradium.ai/pricing) |
| Characters included on cheapest plan | 225,000 chars/mo | Jul 20 | [source](https://gradium.ai/pricing) |
| Free tier quota | 45,000 credits (~1 hour of audio) | Jul 20 | [source](https://gradium.ai/pricing) |
| Enterprise / contact-sales threshold | Enterprise plan: custom pricing | Jul 20 | [source](https://gradium.ai/pricing) |

### Capabilities

| Fact | Value | Verified | Source |
| --- | --- | --- | --- |
| Streaming audio output | ✓  Yes | Jul 20 | [source](https://docs.gradium.ai/guides/text-to-speech) |
| Realtime websocket API | ✓  Yes | Jul 20 | [source](https://docs.gradium.ai/guides/text-to-speech) |
| Voice library size | 66 flagship voices | Jul 20 | [source](https://docs.gradium.ai/guides/voices/flagship-voices.md) |
| Instant voice cloning | ✓  Yes | Jul 20 | [source](https://docs.gradium.ai/guides/voices/custom-voices.md) |
| Professional voice cloning | ✓  Yes | Jul 20 | [source](https://gradium.ai/) |
| Minimum audio for voice cloning | 10 seconds | Jul 20 | [source](https://docs.gradium.ai/guides/voices/custom-voices.md) |
| Languages supported | 5 languages | Jul 20 | [source](https://docs.gradium.ai/guides/voices/custom-voices.md) |
| SSML support | ✓  partial | Jul 20 | [source](https://docs.gradium.ai/guides/text-to-speech) |
| Word-level timestamps | ✓  Yes | Jul 20 | [source](https://docs.gradium.ai/guides/text-to-speech) |
| Pronunciation dictionaries | ✓  Yes | Jul 20 | [source](https://docs.gradium.ai/llms.txt) |

### Compliance & trust

| Fact | Value | Verified | Source |
| --- | --- | --- | --- |
| Commercial use on free tier | ✗  No | Jul 20 | [source](https://gradium.ai/pricing) |
| Self-host / on-prem option | ✓  Yes | Jul 20 | [source](https://gradium.ai/) |

### Build experience

| Fact | Value | Verified | Source |
| --- | --- | --- | --- |
| Official SDKs | Python SDK (documented) | Jul 20 | [source](https://docs.gradium.ai/guides/text-to-speech) |
| Concurrency on base plan | 2-5 simultaneous TTS requests (Free through S); M: 10; L: 15 | Jul 20 | [source](https://gradium.ai/pricing) |
| Output formats | pcm (48kHz default | Jul 20 | [source](https://docs.gradium.ai/guides/text-to-speech) |
| Max input per request | Single TTS/STT session up to 300 seconds | Jul 20 | [source](https://docs.gradium.ai/guides/limits.md) |

Source: https://www.versusref.com/tts/tools/gradium/