Model comparisons
Gemini 3.8 Flash TTS or Grok TTS, tier by tier: matched prices, request fields, limits and the content policy measured on each.
Gemini 3.8 Flash TTS turns a script into a 24 kHz mono WAV in one of 30 voices, or two voices for a dialogue. Bracketed cues such as [whispering], [sighs] or [laughing] are acted out rather than read aloud.
View model details →View sample outputs →Grok TTS is xAI's text-to-speech, reading a script of up to 15,000 characters in one of 71 preset voices across 20 languages. Speech tags such as laughs and whispers are acted out, and speed runs from 0.7 to 1.5 times.
View model details →View sample outputs →Compare
Start with the input you have, the result you want and your budget. These are the differences that affect that choice.
Compare the published examples, then try the same input on both models with matching settings.
Current price
A start price answers a different question than the one you have. These are the tiers both models publish, matched setting for setting, in US dollars per billed unit with no conversion step in between.
These two bill on different tiers, so there is no row to line up. Each one's own published tiers are listed here instead.
Gemini 3.8 Flash TTS: $0.00032 / output seconds
Grok TTS: $0.018 / thousand characters
About this comparison
Every row here is read from the JSON Schema the endpoint validates against, so it matches what the API will really accept rather than a feature list written by hand.
Swipe horizontally to compare all fields.
| Controls and limits | Gemini 3.8 Flash TTS | Grok TTS |
|---|---|---|
| Supported tasks | text-to-speech | text-to-speech |
| Audio output | Yes | Yes |
| Execution | Submit, then poll or take the callback | Submit, then poll or take the callback |
| Request timeout | 30 minutes | 30 minutes |
| Availability | Live | Live |
Do low-filter models allow every request?
Two separate facts sit behind these labels. The first is what we do, which is nothing: no platform content filter, and no maturity flag to set on a request. The second is what each model does on its own, and that is the only part that varies between these two.
Gemini 3.8 Flash TTS
This model declares no content filter. SpicyAPI forwards the request without adding a platform content scan; legal and consent duties remain with the customer.
Usage note SpicyAPI adds no content filter: scripts are read as written, with nothing softened. You are responsible for the scripts you send and for how you use the resulting audio, including not passing it off as a real person's words.
Grok TTS
This model declares no content filter. SpicyAPI forwards the request without adding a platform content scan; legal and consent duties remain with the customer.
Usage note SpicyAPI adds no content filter: NSFW scripts are read as written. You are responsible for the scripts you send and for how you use the resulting audio, including not passing it off as a real person's words.
Use these content labels to shortlist models, then open each model page for available examples and content-test details.
The label never changes your obligations. Age, consent, real-person likeness and the law where you operate stay with you, and SpicyAPI does not inspect each request.
Can I swap the model ID without changing the request body?
The task lifecycle is shared; the body is not. Each endpoint publishes its own JSON Schema and the API validates against that, so this is the list to reconcile before a switch.
Compare
The model identifiers are google/gemini-3.8-flash-tts/text-to-speech and xai/grok-tts/text-to-speech, and both go in the same field of the same request.
Both run the same way: submit the task, then poll it or take the callback. Queueing and retry logic carry over unchanged.
Both use the same submit-and-track flow, but their required inputs may differ. Check each model page before switching.
One key, one balance, one set of spend caps. Both bill to the same account in US dollars, and the per-key daily, monthly and lifetime limits apply to whichever one you call.
Questions developers ask
The two bill on different tiers, so there is no like-for-like row: Gemini 3.8 Flash TTS starts at $0.00032 / output seconds and Grok TTS at $0.018 / thousand characters. Prices may change; check the estimate shown for your actual settings before submitting.
Gemini 3.8 Flash TTS allows 30 minutes per task and Grok TTS allows 30. Those are ceilings rather than typical times — most requests finish far sooner — but they are what your own client timeout has to survive.
Prices and capabilities shown here come from the current public model catalogue. Check each model page for its latest inputs and examples.