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On October 29, 2026, AssemblyAI launched its first text-to-speech model, AssemblyAI-TTS-1, and made it generally available, targeting real-time telephony voice agents, priced at $15 per 1 million characters, with no annual contract and no concurrency tiers. According to a MarkTechPost report, the model is offered only as a hosted API in us-east-1 and eu-north-1, supports HTTP, WebSocket and OpenAI-compatible interfaces, and includes more than 4,000 voices, instant voice cloning and 6 languages; vendor self-testing shows 93.7% entity accuracy and a median time to first byte of 47 milliseconds, but Cekura's independent benchmark measured a streaming latency of 159 milliseconds and a reading accuracy of 81.5%, and at launch it did not yet support SSML, speaking-rate control or emotion tags. On the same day, Artificial Analysis' Provider Voice Arena evaluation showed AssemblyAI-TTS-1 ranked 12th with an Elo of 1227, ranked 16th with a pronunciation robustness score of 81.7%, and generated at 162 characters per second. Later that day, OpenRouter announced that AssemblyAI-TTS-1 was live, targeting voice agent scenarios, with service available from US or EU nodes.
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AssemblyAI Releases Its First Speech Synthesis Model, AssemblyAI-TTS-1, at $15 per Million CharactersDevelopments
2 confirmed developments
- Source:OpenRouter
AssemblyAI launches its first text-to-speech model, AssemblyAI-TTS-1
Source:MarkTechPost
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Oct 29
MarkTechPost
AssemblyAI Releases Its First Speech Synthesis Model, AssemblyAI-TTS-1, at $15 per Million Characters
AssemblyAI has released its first text-to-speech model, AssemblyAI-TTS-1, and officially opened it up, targeting real-time telephony voice agents, priced at $15 per million characters, with no annual contracts and no concurrency tiers. The model is offered only as a hosted API in us-east-1 and eu-north-1, supports HTTP, WebSocket and OpenAI-compatible interfaces, and comes with more than 4,000 voices, instant voice cloning and 6 languages. The vendor's own testing shows 93.7% entity accuracy and a median time to first byte of 47 ms, but Cekura's independent benchmark measured 159 ms streaming latency and 81.5% reading accuracy, and at launch it does not yet support SSML, speaking-rate control or emotion tags.
OpenRouterRelated discussion
OpenRouter joined this discussion
This post contributes to heat; it is not a formal report or confirmed fact.
OpenRouterFirst-party
AssemblyAI-TTS-1 Launches on OpenRouter
OpenRouter announced that AssemblyAI's first text-to-speech model, AssemblyAI-TTS-1, is now available, targeting voice agent scenarios. According to benchmarks from cekuraAi, the model sits in the best quadrant for speed and accuracy, has the highest naturalness among models priced at $15/1M characters and below, offers 4,000+ voices, and can be served from US or EU nodes.
Artificial Analysis
AssemblyAI's first TTS model AssemblyAI-TTS-1 review: Elo 1227 ranks 12th
AssemblyAI has launched its first TTS model, AssemblyAI-TTS-1, which ranks 12th with an Elo of 1,227 in Artificial Analysis's Provider Voice Arena, and 10th with 1,110 in Controlled Voice. Its pronunciation robustness score is 81.7%, ranking 16th; its generation speed is 162 characters per second, faster than Cartesia Sonic 3.6's 148.6 and Mistral Voxtral 3 TTS's 112.3. Priced at $15/1M characters, only two models among the top 11 in the Provider Voice ranking are cheaper.
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