TTS-1
TTS-1 is a text-to-speech model from OpenAI that converts written text into natural-sounding audio across multiple voices.
OpenAILow-latency text to speech from OpenAI
TTS-1 is a text-to-speech model developed by OpenAI and released in November 2023. It accepts text input and produces spoken audio output, supporting a selection of preset voices. The model has a context window of 4,096 tokens and is priced at $5.00 per one million characters of input text.
TTS-1 is designed for applications where low latency and cost efficiency are priorities, such as real-time voice interfaces, content narration, and accessibility tooling. It is the standard-tier offering in OpenAI's TTS lineup, making it well-suited for high-volume use cases where speed and affordability matter more than the highest possible audio fidelity.
What TTS-1 supports
Text to Speech
Converts written text into spoken audio output. Accepts up to 4,096 tokens of input per request.
Voice Selection
Allows callers to choose from a set of preset voices via a select input. OpenAI offers six built-in voice options for TTS-1.
Low Latency Output
Optimized for real-time or near-real-time audio generation. The FAST tag indicates reduced processing time compared to higher-fidelity alternatives.
Cost-Efficient Pricing
Billed at $5.00 per one million characters, making it suitable for high-volume or production-scale speech generation workloads.
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Get Started FreeCommon questions about TTS-1
What is the context window for TTS-1?
TTS-1 supports a context window of 4,096 tokens per request, which corresponds to roughly 4,096 characters of input text.
How is TTS-1 priced?
TTS-1 is priced at $5.00 per one million characters of input text processed.
What voices are available with TTS-1?
TTS-1 offers a selection of preset voices that can be chosen via a select input. OpenAI provides six built-in voice options: alloy, echo, fable, onyx, nova, and shimmer.
What audio formats does TTS-1 support for output?
TTS-1 supports several output formats including MP3, Opus, AAC, and FLAC, as documented in the OpenAI API reference.
Is TTS-1 suitable for real-time applications?
Yes. TTS-1 is tagged as FAST and is designed for low-latency use cases such as real-time voice interfaces and live narration. For applications where audio quality is the top priority over speed, OpenAI also offers TTS-1-HD.
What people think about TTS-1
Community discussion around OpenAI's TTS models is largely focused on comparisons with open-source and locally-run alternatives, with threads highlighting projects like Qwen3-TTS and Orpheus-FastAPI that offer OpenAI-compatible endpoints. Users frequently discuss latency benchmarks and voice quality as key evaluation criteria when choosing between hosted and self-hosted TTS solutions.
A notable thread on r/singularity flagged that OpenAI quietly released updated versions of its TTS and other audio models dated 2025-12-15, suggesting ongoing iteration on the model family. The Reddit threads found are not exclusively about tts-1 itself, so direct community sentiment about this specific model is limited in the available data.
[Release] Qwen3-TTS: Ultra-Low Latency (97ms), Voice Cloning & OpenAI-Compatible API
Orpheus-FastAPI: Local TTS with 8 Voices & Emotion Tags (OpenAI Endpoint Compatible)
Long consistent Ai Anime is almost here. Wan 2.1 with LoRa. Generated in 720p on 4090
OpenAI just stealth-dropped new "2025-12-15" versions of their Realtime, TTS and Transcribe models in the API.
Thanks to you guys, Soprano TTS now supports OpenAI-compatible endpoint, ONNX, ComfyUI, WebUI, and CLI on CUDA, MPS, ROCm, and CPU!
Parameters & options
Voice to use in TTS
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