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Model infoModelsSnapshot: 15 Oct 2026

ByteDance / Seed TTS

Seed TTS 1.0

First-generation Seed speech synthesis, still selectable in the current TTS API.

Speech & voice
availableClosed weightsText-to-speech
Official documentation (opens in a new tab)Reviewed 12 Oct 2026
5 of 16 specification fields collected
Context windowNot collectedAwaiting source review
Maximum outputNot collectedAwaiting source review
Input billingSee ratesBytePlus Seed Speech
Output billingSee ratesPublished units and conditions 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)
Batch processing
Not collected
Fine-tuning
Not collected
Knowledge cutoff
Not collected
Release date
Not collected
Parameters
Not collected
Architecture
Not collected
Languages
View all 14 entries
  • American English
  • British English
  • Australian English
  • English & Chinese
  • English
  • Chinese
  • Chinese - Beijing
  • Chinese - Canton
  • Chinese - Sichuan
  • Chinese - Taiwan
  • Cantonese
  • Japanese & Spanish
  • Japanese
  • Spanish
Source for Languages (opens in a new tab)

Voice-specific language support; not every voice supports every listed language.

Context caching
SupportedSource for Context caching (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.

BytePlus Seed Speech · Unidirectional streaming HTTP

Provider source (opens in a new tab)
API model ID
seed-tts-1.0

Provider model selector or X-Api-Resource-Id as documented; it is not a user voice ID.

Access
Enable Seed Speech for an eligible BytePlus account and use the documented resource selector. Voice permissions and concurrency limits apply.
Regions
ap-southeast-1 API endpoint; other regions not verified
Service tier
Unidirectional streaming HTTPSource for Service tier (opens in a new tab)
Audio formats
PCM, MP3, OGG_OPUSSource for Audio formats (opens in a new tab)

WAV may be accepted but repeated streaming headers make PCM preferable.

Audio sample rates
8,000; 16,000; 22,050; 24,000; 32,000; 44,100; 48,000 HzSource for Audio sample rates (opens in a new tab)

Shared API values. The TTS 2.0 overview lists a narrower set; verify the chosen model/format combination.

Streaming
SupportedSource for Streaming (opens in a new tab)
API aliases
volc.service_type.1000009Source for API aliases (opens in a new tab)

Prices retain their published currencies and billing units below.

Published billing units · original currency · observed 12 Oct 2026
CategoryUsageRateUnit
Speech synthesisInput text1$30.001M characters

Rate conditions

  1. Published Seed TTS service-level PAYG rate; no model-version surcharge is stated. Letters, Chinese characters, punctuation, spaces and line breaks count. Optional concurrency and prepaid packages are separate.
Pricing source (opens in a new tab)

Data & enterprise terms

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

BytePlus Seed Speech · Bidirectional streaming WebSocket

Provider source (opens in a new tab)
API model ID
seed-tts-1.0

Provider model selector or X-Api-Resource-Id as documented; it is not a user voice ID.

Access
Enable Seed Speech for an eligible BytePlus account and use the documented resource selector. Voice permissions and concurrency limits apply.
Regions
ap-southeast-1 API endpoint; other regions not verified
Service tier
Bidirectional streaming WebSocketSource for Service tier (opens in a new tab)
Audio formats
PCM, MP3, OGG_OPUSSource for Audio formats (opens in a new tab)

WAV may be accepted but repeated streaming headers make PCM preferable.

Audio sample rates
8,000; 16,000; 22,050; 24,000; 32,000; 44,100; 48,000 HzSource for Audio sample rates (opens in a new tab)

Shared API values. The TTS 2.0 overview lists a narrower set; verify the chosen model/format combination.

Streaming
SupportedSource for Streaming (opens in a new tab)
API aliases
volc.service_type.1000009Source for API aliases (opens in a new tab)

Prices retain their published currencies and billing units below.

Published billing units · original currency · observed 12 Oct 2026
CategoryUsageRateUnit
Speech synthesisInput text1$30.001M characters

Rate conditions

  1. Published Seed TTS service-level PAYG rate; no model-version surcharge is stated. Letters, Chinese characters, punctuation, spaces and line breaks count. Optional concurrency and prepaid packages are separate.
Pricing source (opens in a new tab)

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.

BytePlus Seed Speech · Unidirectional streaming HTTP

seed-tts-1.0
Documented
Support evidence (opens in a new tab)
How it works
Repeated-text synthesized-audio cacheSource for How it works (opens in a new tab)
Minimum reusable input
Not collected

No minimum text length documented.

Lifetime & refresh
1 hourSource for Lifetime & refresh (opens in a new tab)
How to enable it
Set additions.cache_config.text_type=1 and use_cache=true.Source for How to enable it (opens in a new tab)
Usage fields
Identical text reuses previously synthesized audio.Source for Usage fields (opens in a new tab)
Billing rules
Not collected

No cache-hit discount or separate storage charge verified.

Limits & data boundaries
Cached responses do not include timestamps. This is audio reuse, not LLM prompt caching.Source for Limits & data boundaries (opens in a new tab)

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

Caching reviewed 12 Oct 2026

BytePlus Seed Speech · Bidirectional streaming WebSocket

seed-tts-1.0
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.

Voice choices

128 voices

Choose a voice within Seed TTS 1.0. These are API voice identifiers, not additional model releases. Source links document each voice.

Published voice catalog
Voice / API IDLanguage & accentDelivery
Candiceen_female_candice_emo_v2_mars_bigttsAmerican EnglishEmotion; Warm; affectionate , angry , ASMR , chat , excited , happy , neutral , warmVoice source (opens in a new tab)
Serenaen_female_skye_emo_v2_mars_bigttsAmerican EnglishEmotion; Vivid; affectionate , angry , ASMR , chat , excited , happy , neutral , warm , sadVoice source (opens in a new tab)
Glenen_male_glen_emo_v2_mars_bigttsAmerican EnglishEmotion; Clear; affectionate , angry , ASMR , chat , excited , happy , neutral , warm , sadVoice source (opens in a new tab)
Sylusen_male_sylus_emo_v2_mars_bigttsAmerican EnglishEmotion; Deep; affectionate , angry , ASMR , authoritative , chat , excited , happy , neutral , warm , sadVoice source (opens in a new tab)
Coreyen_male_corey_emo_v2_mars_bigttsBritish EnglishEmotion; Clear; affectionate , angry , ASMR , authoritative , chat , excited , happy , neutral , warm , sadVoice source (opens in a new tab)
Nadiaen_female_nadia_tips_emo_v2_mars_bigttsBritish EnglishEmotion; Sweet; affectionate , angry , ASMR , chat , excited , happy , neutral , warm , sadVoice source (opens in a new tab)
Laurenen_female_lauren_moon_bigttsAmerican EnglishGeneral; VividVoice source (opens in a new tab)
Energetic Male IIen_male_campaign_jamal_moon_bigttsAmerican EnglishGeneral; ClearVoice source (opens in a new tab)

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 from the native hosted model/resource identifier and the reviewed ByteDance/ByteDance-Seed public-checkpoint inventories. These inventories contain no matching released checkpoint; this is not an explicit weight-license declaration.

Classification evidence (opens in a new tab)

Sources reviewed