Grok TTS
Grok TTS is SpaceXAI's text-to-speech model with five expressive voices, speech tags, and telephony codec support, available through Vercel AI Gateway.
- Input price
- Input $15, Per 1M characters
import { experimental_generateSpeech as generateSpeech } from 'ai';import { gateway } from '@ai-sdk/gateway';import { writeFile } from 'node:fs/promises';
const result = await generateSpeech({ model: gateway.speechModel('spacexai/grok-tts'), text: 'Hello from the Vercel AI Gateway!', voice: 'eve',});
await writeFile('speech.mp3', result.audio.uint8Array);Copy link to headingPlayground
Try out Grok TTS by SpaceXAI. Usage is billed to your team at API rates. Free users (those who haven't made a payment) get $5 of credits every 30 days.
Grok TTS
Your generated audio will appear here
Copy link to headingProviders
Route requests across multiple providers. Copy a provider slug to set your preference. Visit the docs for more info. Using a provider means you agree to their terms, listed under Legal.
Copy link to headingMore models by SpaceXAI
| Model |
|---|
| 500K | $2/M+1 more | $6/M+1 more | Read$0.50/M | $5/K | +1 | | 08/12/2026 | |||||||
| 500K | $2/M+1 more | $6/M+1 more | Read$0.30/M | $5/K | +3 | | 07/08/2026 | |||||||
| 1M | $1.25/M+1 more | $2.50/M+1 more | Read$0.20/M | $5/K | +3 |  | 04/30/2026 | |||||||
| 2M | $1.25/M+1 more | $2.50/M+1 more | Read$0.20/M | $5/K | +2 | | 03/10/2026 | |||||||
| 1M | $0.20/M | $0.50/M | Read$0.05/M | — | +1 | | 11/19/2025 | |||||||
| 1M | $0.20/M | $0.50/M | Read$0.05/M | — | +2 | | 11/19/2025 |
Copy link to headingAbout Grok TTS
Grok TTS is SpaceXAI's text-to-speech model, released March 16, 2026 and available through AI Gateway. Five expressive voices cover different tones and characters. Speech tags give you control over expression and delivery, and telephony codec support makes Grok TTS a fit for phone systems and IVR flows. Text to speech through AI Gateway is in beta, so access is rolling out gradually.
Integration uses the AI SDK's experimental_generateSpeech function, available on the canary releases of the AI SDK. Set the voice, such as eve, and an outputFormat like mp3 or wav. Optional instructions, speed, and language settings adjust how the speech sounds. Unsupported options surface in warnings on the result instead of failing the request. A REST endpoint returns base64-encoded audio if you're not using the AI SDK.
Billing is per input character, so cost scales with the length of the text you synthesize. See the pricing panel on this page for current rates. For live conversation, grok-voice-think-fast-1.0 streams speech both ways, and grok-stt covers the transcription direction.
Copy link to headingWhat To Consider When Choosing a Provider
- Configuration: Audio returns base64-encoded in a single response through AI Gateway. Streaming audio output isn't supported, so progressive playback needs buffering on your side. Billing is per input character, and long documents scale cost linearly with text length.
- Configuration: Text to speech is in beta, and AI SDK support ships on canary releases. Voice and option support can vary, and unsupported options come back as warnings rather than errors, so check
result.warningsduring development. - Zero Data Retention: Zero Data Retention is offered on a per-provider and model basis. See the documentation for details.
- Authentication: AI Gateway authenticates requests using an API key or OIDC token. You do not need to manage provider credentials directly.
Copy link to headingWhen to Use Grok TTS
Best for
- Voiceovers and Narration: Convert articles, scripts, or docs into spoken audio files
- Telephony and IVR Audio: Codec support targets phone-system playback paths
- Expressive Delivery Control: Five voices plus speech tags shape tone and delivery
- Spoken App Responses: Generate audio replies from a server route with one call
Consider alternatives when
- Two-Way Voice Sessions:
grok-voice-think-fast-1.0streams speech in and out in real time - Audio Transcription:
grok-sttconverts recorded audio into text instead - Streamed Audio Playback: AI Gateway returns complete audio files rather than progressive streams
Copy link to headingConclusion
Grok TTS turns text into expressive spoken audio through AI Gateway. Five voices, speech tags, and telephony codec support cover narration, app responses, and phone systems. Call the AI SDK's generateSpeech function with a voice and output format, and check current per-character rates on this page.
Copy link to headingFrequently Asked Questions
How many voices does Grok TTS offer?
Grok TTS offers five expressive voices, such as
eve. Set thevoiceoption ingenerateSpeechto choose one.What are speech tags in Grok TTS?
Speech tags are controls for expression and delivery in generated speech. Combined with the expressive voices, they let you adjust how Grok TTS reads your text.
What audio formats does Grok TTS support?
Set
outputFormatto a format likemp3orwav. Grok TTS also supports telephony codecs for phone-system audio, and unsupported options are reported inwarnings.How do I generate speech with Grok TTS?
Use the AI SDK's
experimental_generateSpeechfunction with your text, avoice, and anoutputFormat, then saveresult.audio.uint8Array. A REST endpoint returns base64-encoded audio if you're not using the AI SDK.What does Grok TTS cost?
Billing is per input character, so cost scales with text length. See the pricing panel on this page for current rates.
How do I authenticate with Grok TTS through Vercel AI Gateway?
Use your Vercel AI Gateway API key with
spacexai/grok-ttsas the model identifier. AI Gateway handles provider routing automatically.Does Vercel AI Gateway support Zero Data Retention for Grok TTS?
Zero Data Retention is not currently available for this model. Zero Data Retention is offered on a per-provider basis. See https://vercel.com/docs/ai-gateway/capabilities/zdr for details.