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Voice Design
Create a voice from a written description, no audio sample needed. Describe the accent, age and character you need, generate up to five candidates, and keep your favourite. The voice works with the same Text-to-Speech endpoint as any catalogue voice.In our blind listening evaluation, native speakers judged how well voices matched accent prompts. Gradium achieved a 72.6% win rate against ElevenLabs, Inworld, MiniMax and Fish Audio, counting ties as half a win, and ranked first in English, French, Spanish, Portuguese and German.See the Voice Design guide to get started.
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Longer sessions
A session can last up to 3000 seconds. See Limits.
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New Text-to-Speech model
A new Gradium Text-to-Speech model is live and is now the default. Existing voices, including custom voices, work as-is.The model reads the structured entities that break voice agents in production, such as phone numbers, email addresses, IBANs and reference codes, with no pre-processing or text normalization needed. On Coval, time to first audio P50 is 216 ms, 170 ms faster than the previous model.Full benchmarks, audio samples and the open-sourced evaluation set are in the release post. To get started, see Text-to-Speech.
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Always set a language for transcription
Speech-to-Text requests now require a language in json_config. Our ASR gives its best results when the language is known, so set it whenever you can: en, fr, es, pt, or de. When the language is not known ahead of time, pass any and the model detects it from the audio. Requests that already set a language or any are unaffected. See Transcription Settings.The Resources menu on the website now links straight to these release notes.
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Gradium Studio and website updates
  • Model selector in Gradium Studio: the Text-to-Speech page now has a Model dropdown to switch between the production model and gradium-tts-beta, showing each model_name with a copy button.
  • Shareable studio links: pre-configure a session with ?voice=, ?model_name=, ?text= and ?language= and share the full setup as a single link. Links now survive login and signup, so they work for recipients who are not signed in yet; voice IDs with ready-made links are on Flagship Voices.
  • Onboarding for new accounts: signing up or accepting an invitation now starts with a short three-step setup to get you up and running quickly.
  • Contact and feedback without leaving the studio: the profile menu now has Support > Contact and Support > Feedback, the same forms as on the website, with attachments.
  • System appearance: a new System theme option in the studio follows your OS light or dark preference live.
  • Feedback page on the website: gradium.ai/feedback is a standalone form for product feedback, open to everyone.
  • Live Translation demo: pick the target language and the output voice in one “Translate to … with the voice of …” row on the website demo.
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Improved translation models
Our live translation models (stt-translate for translated transcription and s2s-translate for Speech-to-Speech) now produce more natural, more accurate translations, with better context understanding across a conversation. The quality gains are most noticeable on conversational speech.See Speech-to-Speech and the Speech-to-Text overview to get started.
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Gradium TTS public beta
A new Gradium Text-to-Speech model is available in public beta. It handles complex text natively, with no pre-processing or normalization on your side: phone numbers in national and international formats, email addresses, IBAN numbers, time expressions, reference codes, measurements, URLs and ordinals.The beta is available through the API and in Gradium Studio. To use it from the API, set model_name to gradium-tts-beta in your setup message, over both the SDK and the WebSocket API. Your existing voices, including custom voices, work as-is. On the API the current production model remains the default, so nothing changes unless you opt in.See Installation and the TTS WebSocket setup to get started. Everyone who sends feedback during the beta receives 1M Gradium credits.
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New Speech-to-Text model
A new Speech-to-Text model is now live on the standard endpoint. Transcription is more robust on low volume audio, so soft speakers and far field microphones are recognised with improved reliability. Endpointing is more reactive, so the end of an utterance is detected sooner and voice agents can start responding with less delay.See Turn-Taking for using semantic VAD signals to decide when a speaker has finished.
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Keyword Boosting for Speech-to-Text
Get the vocabulary specific to your product transcribed correctly: brand and product names, people, places, drugs, and jargon. Pass a dictionary of the terms you care about in your STT json_config, and the model gives them priority while decoding, in real time, with no retraining. Rare, specific words that a general model rarely sees now come through correctly.The keywords block takes a words dictionary and a boost weight. boost is applied in log-probability space, so its effect is exponential and a small value goes a long way. We recommend a boost of 3. A dictionary holds up to 500 single-token entries, matched by exact case and accent.Dictionaries can also be saved in Gradium Studio under Vocabulary, in the Keyword boost tab, then used in a session by passing their id as keyword_boost_id.See the Keyword Boosting recipe and Transcription Settings for details.
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Upgraded default TTS model
Gradium TTS now runs on an upgraded default model focused on more expressive speech and better reliable pronunciation for production voice agents.Improved natural prosody, phrasing, intonation, and pacing. This is especially noticeable in conversational turns and longer passages.The model is better at spelling out email addresses, reference numbers, confirmation codes, and acronyms such as API, SQL, and URL.The upgraded model is now the default. If your integration uses the default model, you are already on the new Gradium TTS model with no code changes required.Every voice from the previous model generation is available on the upgraded model, including custom voices. You do not need to re-clone or recreate voices.Integrations pinned to a specific model can switch by changing the model identifier. To stay on the previous model temporarily, set model_name to gradium-tts-202602. The previous model will be gradually phased out over the next few weeks.
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Gradium API and Studio updates
We’re excited to announce major updates to the Gradium API and Gradium Studio, delivering enhanced text-to-speech (TTS) and speech-to-text (STT) capabilities for developers and enterprises.Advanced TTS and STT ModelsExperience our latest text-to-speech model and speech recognition model with improved audio quality, accuracy, and natural-sounding voice generation. Perfect for voice applications, transcription services, and conversational AI. Now by default.Custom Pronunciation DictionariesTake control of speech synthesis with pronunciation dictionaries. Ensure brand names, technical terminology, and industry-specific acronyms are pronounced correctly every time. Ideal for healthcare, finance, and industry specific applications.WebSocket Multiplexing for Real-Time AudioBoost performance with multiplexing support: process multiple TTS or STT requests simultaneously over a single WebSocket connection. Reduce latency, minimize connection overhead, and scale efficiently for high-volume applications.Gradium Referral ProgramLove Gradium? Join our referral program: share Gradium with your network and earn up to 9M API credits while your referrals get exclusive discounts. Win-win for developers and businesses alike.AWS Marketplace & SageMaker AI DeploymentDeploy Gradium TTS and ASR models directly on AWS SageMaker with full bidirectional streaming support. Accelerate your deployment timeline while keeping your voice AI infrastructure secure within your private cloud network. Now available on AWS Marketplace.Feedbacks are always welcome, do not hesitate to join our discord channel!