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Model infoModelsSnapshot: 15 Oct 2026

Smallest AI / Lightning

Lightning V4

Beta speech synthesis conditioned on earlier dialogue turns, listed in the public model registry. Its production API contract is not yet verified.

Speech & voice
previewClosed weightsText-to-speech
Official documentation (opens in a new tab)Reviewed 13 Oct 2026
6 of 19 specification fields collected
Context windowNot collectedAwaiting source review
Maximum outputNot collectedAwaiting source review
Input billingNot collectedSmallest AI model registry
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
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
Not collected
Batch processing
Not collected
Fine-tuning
Not collected
Knowledge cutoff
Not collected
Release date
Not collected
Parameters
Not collected
Architecture
Not collected
Languages
EnglishSource for Languages (opens in a new tab)

Registry language metadata can lag the current model card; auto is routing metadata, not another language.

Context caching
Not collected
Native model options
lightning-v4Source for Native model options (opens in a new tab)

Registry identifier uses hyphens; unified TTS request selectors for v3.1/v3.2 use underscores.

Voice cloning
Not supportedSource for Voice cloning (opens in a new tab)

Voice cloning is not evidence of user access to base-model fine-tuning. Legacy flags do not imply current clone creation works.

Stock voice catalog
12 public stock voices mapped to lightning-v4 on 2026-10-13Source for Stock voice catalog (opens in a new tab)

Snapshot count, not a permanent service limit. Presets are not independent model checkpoints.

Access & pricing

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

Smallest AI model registry

Provider source (opens in a new tab)
API model ID
Not collected

No pinned inference selector verified for this access route.

Access
Listed as beta in the public voice/model registry; request provider access. No verified public inference selector, price or API limit yet.
Regions
Automatic routing to Mumbai, India or Oregon, USA; api.india.smallest.ai and api.us.smallest.ai pin a region. Language availability can differ by region.

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

Data & enterprise terms

Current general provider terms are linked; a model-specific historical or beta retention contract has not been verified.

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.

Smallest AI model registry

Not verified

No discounted prompt-cache contract verified for this model/access route. Audio continuity and model-weight storage are separate features.

How it works
Not collected

No discounted prompt-cache contract verified for this model/access route. Audio continuity and model-weight storage are separate features.

Minimum reusable input
Not collected

No discounted prompt-cache contract verified for this model/access route. Audio continuity and model-weight storage are separate features.

Lifetime & refresh
Not collected

No discounted prompt-cache contract verified for this model/access route. Audio continuity and model-weight storage are separate features.

How to enable it
Not collected

No discounted prompt-cache contract verified for this model/access route. Audio continuity and model-weight storage are separate features.

Usage fields
Not collected

No discounted prompt-cache contract verified for this model/access route. Audio continuity and model-weight storage are separate features.

Billing rules
Not collected

No discounted prompt-cache contract verified for this model/access route. Audio continuity and model-weight storage are separate features.

Limits & data boundaries
Not collected

No discounted prompt-cache contract verified for this model/access route. Audio continuity and model-weight storage are separate features.

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

Voice choices

12 voices

Choose a voice within Lightning V4. These are API voice identifiers, not additional model releases. Source links document each voice.

Published voice catalog
Voice / API IDLanguage & accentDelivery
Brannockbrannockenglish
american		Provider voice label: male. Language tags describe the voice; they do not override endpoint language restrictions.Voice source (opens in a new tab)
Posyposyenglish
american		Provider voice label: female. Language tags describe the voice; they do not override endpoint language restrictions.Voice source (opens in a new tab)
Tildatildaenglish
american		Provider voice label: female. Language tags describe the voice; they do not override endpoint language restrictions.Voice source (opens in a new tab)
Marenmarenenglish
american		Provider voice label: female. Language tags describe the voice; they do not override endpoint language restrictions.Voice source (opens in a new tab)
Birdiebirdieenglish
american		Provider voice label: female. Language tags describe the voice; they do not override endpoint language restrictions.Voice source (opens in a new tab)
Willawillaenglish
american		Provider voice label: female. Language tags describe the voice; they do not override endpoint language restrictions.Voice source (opens in a new tab)
Pippapippaenglish
american		Provider voice label: female. Language tags describe the voice; they do not override endpoint language restrictions.Voice source (opens in a new tab)
Honorhonorenglish
american		Provider voice label: female. Language tags describe the voice; they do not override endpoint language restrictions.Voice 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

Smallest retains rights in its AI models and prohibits model extraction. Its model cards name Smallest as developer; Electron, Hydra and Lightning v3.1 explicitly use proprietary licenses. Commercial self-hosting requires licensed artifacts and a license proxy, not an open-weight grant.

Classification evidence (opens in a new tab)

Sources reviewed