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Model infoModelsSnapshot: 15 Oct 2026

Hume AI / Octave

Octave 2

Multilingual speech synthesis with word and phoneme timing. The preview API is scheduled to close in November 2026.

deprecatedClosed weightsText-to-speech
Official documentation (opens in a new tab)Reviewed 13 Oct 2026
11 of 22 specification fields collected
Text input limit5,000 characters per utteranceSee specification notes below
Languages11 listedFull language list in specifications
Input billingNot collectedHume API
Output billingNot collectedNo inferred price

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
Reasoning
Not collected
Tool calling
Not collected
Structured output
Not collected
Batch processing
Not collected
Fine-tuning
Not collected
Knowledge cutoff
Not collected
Parameters
Not collected
Architecture
Not collected
Languages
English, Japanese, Korean, Spanish, French, Portuguese, Italian, German, Russian, Hindi, ArabicSource for Languages (opens in a new tab)
Context caching
Not collected
Usage metering
Subscription includes TTS, EVI and voice features, with plan allowances and overages. Current numeric rates remain unverified because the public pricing page redirects to the homepage.Source for Usage metering (opens in a new tab)
Maximum prompt characters
5,000 characters per utteranceSource for Maximum prompt characters (opens in a new tab)
Request limits
Description: 1,000 characters per utterance. Up to 5 generations per request. Request rate depends on the subscription.Source for Request limits (opens in a new tab)
Word timestamps
SupportedSource for Word timestamps (opens in a new tab)

Word and phoneme timestamp requests are documented only for Octave 2.

Voice controls
Voice must be specified with version 2. Speed and trailing silence controls; the overview lists acting directions as coming soon.Source for Voice controls (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.

API model ID
2

Value of the version request field, not a generic model field.

Access
Hume API key required; subscription and account limits apply.
Regions
Deployment region and customer-specific residency are not established by the reviewed endpoint documentation.
API endpoint URL
https://api.hume.ai/v0/tts/fileSource for API endpoint URL (opens in a new tab)
Maximum prompt characters
5,000 characters per utteranceSource for Maximum prompt characters (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.

API model ID
2

Value of the version request field, not a generic model field.

Access
Hume API key required; subscription and account limits apply.
Regions
Deployment region and customer-specific residency are not established by the reviewed endpoint documentation.
API endpoint URL
https://api.hume.ai/v0/ttsSource for API endpoint URL (opens in a new tab)
Maximum prompt characters
5,000 characters per utteranceSource for Maximum prompt characters (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.

API model ID
2

Value of the version request field, not a generic model field.

Access
Hume API key required; subscription and account limits apply.
Regions
Deployment region and customer-specific residency are not established by the reviewed endpoint documentation.
API endpoint URL
https://api.hume.ai/v0/tts/stream/fileSource for API endpoint URL (opens in a new tab)
Maximum prompt characters
5,000 characters per utteranceSource for Maximum prompt characters (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.

API model ID
2

Value of the version request field, not a generic model field.

Access
Hume API key required; subscription and account limits apply.
Regions
Deployment region and customer-specific residency are not established by the reviewed endpoint documentation.
API endpoint URL
https://api.hume.ai/v0/tts/stream/jsonSource for API endpoint URL (opens in a new tab)
Maximum prompt characters
5,000 characters per utteranceSource for Maximum prompt characters (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.

API model ID
2

Value of the version request field, not a generic model field.

Access
Hume API key required; subscription and account limits apply.
Regions
Deployment region and customer-specific residency are not established by the reviewed endpoint documentation.
API endpoint URL
wss://api.hume.ai/v0/tts/stream/inputSource for API endpoint URL (opens in a new tab)
Maximum prompt characters
5,000 characters per utteranceSource for Maximum prompt characters (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.

Hume API

2
Not verified

No verified provider-side caching policy or cache rate. Continuation, stored chats and downloaded audio do not establish prompt caching.

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.

Hume API

2
Not verified

No verified provider-side caching policy or cache rate. Continuation, stored chats and downloaded audio do not establish prompt caching.

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.

Hume API

2
Not verified

No verified provider-side caching policy or cache rate. Continuation, stored chats and downloaded audio do not establish prompt caching.

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.

Hume API

2
Not verified

No verified provider-side caching policy or cache rate. Continuation, stored chats and downloaded audio do not establish prompt caching.

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.

Hume API

2
Not verified

No verified provider-side caching policy or cache rate. Continuation, stored chats and downloaded audio do not establish prompt caching.

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 exact named Hume API release/service from provider documentation and its public weight inventory. No weights for this identity were identified; public TADA releases are excluded. A service record does not assert a separately disclosed checkpoint or parameter count.

Classification evidence (opens in a new tab)

Lifecycle dates

Preview launch1 Oct 2025Source (opens in a new tab)
TTS and EVI sunset announced2 Oct 2026Source (opens in a new tab)
Scheduled API access end at 12:01 a.m. EST13 Nov 2026Source (opens in a new tab)

Sources reviewed