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Model infoModelsSnapshot: 15 Oct 2026

Inworld AI / TTS-1

Realtime TTS-1 Max

Historical autoregressive speech model whose native selector was discontinued in June 2026 and now routes to a newer model.

retiredClosed weightsText-to-speech
Official documentation (opens in a new tab)Reviewed 13 Oct 2026
8 of 18 specification fields collected
Context windowNot collectedAwaiting source review
Maximum outputNot collectedAwaiting source review
Input billingNot collectedInworld 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
Streaming
SupportedSource for Streaming (opens in a new tab)

Historical streaming inference, not evidence of current original-model access.

Batch processing
Not collected
Fine-tuning
Not collected
Knowledge cutoff
Not collected
Release date
Not collected
Parameters
8.8 billionSource for Parameters (opens in a new tab)

Total of all inference components, not only the SpeechLM backbone.

Architecture
Autoregressive Transformer SpeechLM with shared 1D audio-codec encoder/decoder and 48 kHz super-resolutionSource for Architecture (opens in a new tab)
Languages
English · production, Chinese · production, Korean · production, Dutch · production, French · production, Spanish · production, Japanese · experimental, German · experimental, Italian · experimental, Polish · experimental, Portuguese · experimentalSource for Languages (opens in a new tab)
Context caching
Not collected
Audio sample rates
48 kHz native speech generationSource for Audio sample rates (opens in a new tab)
Voice cloning
Historical zero-shot conditioning from reference audio and transcriptSource for Voice cloning (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
inworld-tts-1-max
Access
Retired June 15, 2026; native requests automatically route to newer models. Original checkpoint access is not established.
Regions
General API region not pinned by these contracts. EU and India residency are enterprise offerings, not assumed for every request.

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

Data & enterprise terms

Inworld terms exclude nonpublic inputs/outputs from general model training, with feedback and trust/safety exceptions. ZDR is configurable and has product-specific exceptions; it is not a universal default. Pricing lists a Growth add-on, while the ZDR guide limits self-serve controls to Enterprise/Enterprise Trial. Confirm the actual workspace setting and contract. Clone samples and voice-design creation inputs are retained.

Read the service policy (opens in a new tab)
API model ID
inworld/inworld-tts-1-max
Access
Retired on LiveKit June 1, 2026. This predates the native retirement and is not current original-model access.
Regions
Global. The model row does not list a dedicated EU endpoint.
Languages
View all 15 entries
  • en
  • es
  • fr
  • ko
  • nl
  • zh
  • de
  • it
  • ja
  • pl
  • pt
  • ru
  • hi
  • he
  • ar
Source for Languages (opens in a new tab)

Host language table is retained independently of native tiers and locale aliases.

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

Data & enterprise terms

LiveKit documents zero retention for inference content by default, including underlying providers. Optional observability and custom-voice storage have separate handling.

Read the service policy (opens in a new tab)

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.

Inworld API

inworld-tts-1-max
Not verified

No model-specific prompt-cache mechanism, lifetime or cached-token price established. Free synthesisContext text and reusable voice profiles do not establish prompt caching.

How it works
Not collected

No model-specific prompt-cache mechanism, lifetime or cached-token price established. Free synthesisContext text and reusable voice profiles do not establish prompt caching.

Minimum reusable input
Not collected

No model-specific prompt-cache mechanism, lifetime or cached-token price established. Free synthesisContext text and reusable voice profiles do not establish prompt caching.

Lifetime & refresh
Not collected

No model-specific prompt-cache mechanism, lifetime or cached-token price established. Free synthesisContext text and reusable voice profiles do not establish prompt caching.

How to enable it
Not collected

No model-specific prompt-cache mechanism, lifetime or cached-token price established. Free synthesisContext text and reusable voice profiles do not establish prompt caching.

Usage fields
Not collected

No model-specific prompt-cache mechanism, lifetime or cached-token price established. Free synthesisContext text and reusable voice profiles do not establish prompt caching.

Billing rules
Not collected

No model-specific prompt-cache mechanism, lifetime or cached-token price established. Free synthesisContext text and reusable voice profiles do not establish prompt caching.

Limits & data boundaries
Not collected

No model-specific prompt-cache mechanism, lifetime or cached-token price established. Free synthesisContext text and reusable voice profiles do not establish prompt caching.

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

LiveKit Inference

inworld/inworld-tts-1-max
Not verified

No model-specific prompt-cache mechanism, lifetime or cached-token price established. Free synthesisContext text and reusable voice profiles do not establish prompt caching.

How it works
Not collected

No model-specific prompt-cache mechanism, lifetime or cached-token price established. Free synthesisContext text and reusable voice profiles do not establish prompt caching.

Minimum reusable input
Not collected

No model-specific prompt-cache mechanism, lifetime or cached-token price established. Free synthesisContext text and reusable voice profiles do not establish prompt caching.

Lifetime & refresh
Not collected

No model-specific prompt-cache mechanism, lifetime or cached-token price established. Free synthesisContext text and reusable voice profiles do not establish prompt caching.

How to enable it
Not collected

No model-specific prompt-cache mechanism, lifetime or cached-token price established. Free synthesisContext text and reusable voice profiles do not establish prompt caching.

Usage fields
Not collected

No model-specific prompt-cache mechanism, lifetime or cached-token price established. Free synthesisContext text and reusable voice profiles do not establish prompt caching.

Billing rules
Not collected

No model-specific prompt-cache mechanism, lifetime or cached-token price established. Free synthesisContext text and reusable voice profiles do not establish prompt caching.

Limits & data boundaries
Not collected

No model-specific prompt-cache mechanism, lifetime or cached-token price established. Free synthesisContext text and reusable voice profiles do not establish prompt caching.

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

Inworld grants limited service/model access and reserves model IP under its proprietary terms, including separately contracted customer-hosted deployment. The TTS-1 research release publishes training/modeling code, not the production TTS model weights. Current TTS/STT release identities are established in the native catalog; routed third-party models are excluded.

Classification evidence (opens in a new tab)

Lifecycle dates

Technical report dated22 Jul 2025Source (opens in a new tab)
Introduction article dated15 Aug 2025Source (opens in a new tab)
Quality and voice similarity update22 Aug 2025Source (opens in a new tab)
Native models discontinued; requests rerouted15 Jun 2026Source (opens in a new tab)

Sources reviewed