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Model infoModelsSnapshot: 15 Oct 2026

StepFun / StepAudio

StepAudio 3 Gen Preview

StepAudio 3 Gen Preview, a StepFun hosted speech generation service.

Music generationSound effectsSpeech & voice
previewClosed weightsSpeech generationSound effects generationMusic generation
Official documentation (opens in a new tab)Reviewed 12 Oct 2026
6 of 19 specification fields collected
Text input limitScripts: 1,000 characters; instruction: 500; role names and descriptions combined: 500.See specification notes below
LanguagesNot collectedAwaiting source review
Input billingSee billing notesStepFun China
Output billingSee billing notesAccess and billing notes below

Specifications

Provider-documented facts. “Not collected” means we have not verified that field yet, not that the feature is unsupported.

Context / input limit
Not collected
Maximum output
Not collected
Input modalities
TextSource for Input modalities (opens in a new tab)
Output modalities
AudioSource for Output modalities (opens in a new tab)
Reasoning
Not collected
Tool calling
Not collected
Structured output
Not collected
Streaming
SupportedSource for Streaming (opens in a new tab)

HTTP audio or SSE output; WebSocket is not supported.

Batch processing
Not collected
Fine-tuning
Not collected
Knowledge cutoff
Not collected
Release date
Not collected
Parameters
Not collected
Architecture
Not collected
Languages
Not collected
Context caching
Not collected
Published price
Temporarily free preview; paid replacement planned. No end date is published.Source for Published price (opens in a new tab)
Output formats
WAV, FLAC, Opus, MP3, PCMSource for Output formats (opens in a new tab)
Maximum prompt characters
Scripts: 1,000 characters; instruction: 500; role names and descriptions combined: 500.Source for Maximum prompt characters (opens in a new tab)

Access & pricing

Prices belong to an endpoint and billing tier. A provider listing does not guarantee access for every account or region.

StepFun China

Provider source (opens in a new tab)
API model ID
stepaudio-3-gen-preview
Access
StepFun account and regional API key required. Documented availability, not a paid inference verification.
Regions
China platform (.com); deployment geography and data residency are not established by the hostname.
API endpoint URL
POST https://api.stepfun.com/v1/audio/generateSource for API endpoint URL (opens in a new tab)

Endpoint pricing has not been collected. Check the provider for applicable rates.

Data & enterprise terms

Retention, training use, regional processing and enterprise terms have not been summarized for this endpoint.

StepFun International

Provider source (opens in a new tab)
API model ID
stepaudio-3-gen-preview
Access
StepFun account and regional API key required. Documented availability, not a paid inference verification.
Regions
International platform (.ai); deployment geography and data residency require account-specific confirmation.
API endpoint URL
POST https://api.stepfun.ai/v1/audio/generateSource for API endpoint URL (opens in a new tab)

Endpoint pricing has not been collected. Check the provider for applicable rates.

Data & enterprise terms

Retention, training use, regional processing and enterprise terms have not been summarized for this endpoint.

Caching

Caching can reuse earlier input processing. Availability, lifetime and billing depend on the endpoint. A cache hit still generates a new response.

01 / INITIAL INPUTProcess & retain

The system processes eligible input and retains reusable state.

02 / LATER REQUESTCheck available state

Reuse depends on matching input, session state and the cache policy.

03 / CACHE HITReuse & generate

Reusing state can reduce repeated work. Any charges follow the billing rules below.

StepFun China

stepaudio-3-gen-preview
Not verified
How it works
Not collected
Minimum reusable input
Not collected
Lifetime & refresh
Not collected
How to enable it
Not collected
Usage fields
Not collected
Billing rules
Not collected
Limits & data boundaries
Not collected

No verified cache rate for this endpoint. An empty rate is not a zero charge.

StepFun International

stepaudio-3-gen-preview
Not verified
How it works
Not collected
Minimum reusable input
Not collected
Lifetime & refresh
Not collected
How to enable it
Not collected
Usage fields
Not collected
Billing rules
Not collected
Limits & data boundaries
Not collected

No verified cache rate for this endpoint. An empty rate is not a zero charge.

What the measurements say

No benchmark observations have been added for this model. We do not turn a vendor description into a performance score.

Latency and throughput depend on the host, request size, reasoning settings and load. There is no measured speed or global usage figure in this record.

The record behind the model

Why it is included

Inferred for this named native commercial service from official model/API documentation and comparison with StepFun’s public model repositories. No release of weights for this exact named service was found in the reviewed inventory. Public Step 3/3.5/3.7, Step-Audio Mini/R1/R1.1, Step1X and StepVideo releases are excluded; this does not assert that every StepFun model is closed.

Classification evidence (opens in a new tab)

Sources reviewed