NEW
·
Lightning TTS v3.1
The Voice that
Passes for Human
Studio-quality speech under 200ms, 16 languages, instant voice cloning preferred 76% over GPT-4o-mini TTS.
Trusted by 100+ enterprises
Voice Agents
Storytelling
Voice over
Lightning TTS v3.1
Generated by Lightning TTS v3.1 in real time · 44.1 kHz · <200ms
Voice Agents
Storytelling
Voice over
Lightning TTS v3.1
Generated by Lightning TTS v3.1 in real time · 44.1 kHz · <200ms
Performance that speaks for itself
Performance that speaks for itself
0.0
0.0
0.0
0.0
%
Beyond GPT-4o-mini TTS
0.0
0.0
0.0
0.0
kHz
Native sample rate
<0
<0
<0
<0
ms
First-chunk latency
0.0
0.0
0.0
0.0
%
Word accuracy
One model.
Every voice use case.
Each card plays a short sample. Hear Lightning
in the context that matters to you.
Each card plays a short sample. Hear Lightning in the context that matters to you.
Voice Agents
Conversational AI that sounds like a real person not a script reader.
0:00/1:34
Voice Agents
Conversational AI that sounds like a real person not a script reader.
0:00/1:34
Customer Service
Warm IVR greetings that build trust from the first second.
0:00/1:34
Customer Service
Warm IVR greetings that build trust from the first second.
0:00/1:34
Audiobooks
Long-form narration with natural prosody and pacing.
0:00/1:34
Audiobooks
Long-form narration with natural prosody and pacing.
0:00/1:34
Media
Presenter-quality voice for intros, ads, and full episodes.
0:00/1:34
Media
Presenter-quality voice for intros, ads, and full episodes.
0:00/1:34
Content
Enhance customer service with AI-powered voice assistance
0:00/1:34
Content
Enhance customer service with AI-powered voice assistance
0:00/1:34
Accessibility
Clear, calm screen reader voice at any speed.
0:00/1:34
Accessibility
Clear, calm screen reader voice at any speed.
0:00/1:34
Your first voice agent in just 5 lines of code
Your first voice agent in just 5 lines of code
WebSocket · SSE · HTTP streaming or batch, your choice.
WebSocket · SSE · HTTP streaming or batch, your choice.
What makes
Lightning v3.1 different
Built for teams that ship voice products
not teams that experiment with them.
Built for teams that ship voice products not teams that
experiment with them.
Broadcast-Quality Audio
44.1 kHz native sample rate. WVMOS score of 5.06 the highest in the Lightning family. sounds like it was recorded in a studio, not synthesized by a machine.
Real-Time, Every Time
<200ms latency at 20 concurrent requests. RTF of 0.3 audio generates 3.3× faster than playback speed. Built for live voice agents, not batch exports.
Voice Cloning
Clone any voice in 5–15 seconds for rapid deployment. Invest 45+ minutes of audio for professional-grade cloning that captures intonation, accent, & emotion.
16 Languages
English, Hindi, Spanish, Tamil, French, German, Arabic, Russian, Italian, Dutch, Polish, Hebrew, Bengali, Gujarati, Kannada, Marathi. Local accents built in, not bolted on.
Lightning v3.1 makes a leap in voice quality
Lightning v3.1 makes
a leap in voice quality
Same text. Two models. Press play on both
the gap is immediately audible.
Same text. Two models. Press play on both the gap is immediately audible.
PREVIOUS VERSION
Lightning v2
Lightning v2
24 kHz · Previous generation
ALL NEW
Lightning v3.1
Lightning v3.1
44.1 kHz · Broadcast quality
Lightning v2
Lightning v3.1
Metrics
Sample Rate
24 kHz
44.1 kHz
Naturalness
4.33 / 5
Pronunciation
4.70 / 5
Intonation
4.71 / 5
Latency
Higher
<200ms
Voice Cloning
Basic
Instant + Pro
Naturalness
Enhanced
Lightning v2
Lightning v3.1
Metrics
Sample Rate
24 kHz
Naturalness
Pronunciation
Intonation
Latency
Higher
Voice Cloning
Basic
Naturalness
Common questions about Lightning TTS
What is Lightning TTS and how does it work?
Lightning TTS is a real-time text-to-speech model built by Smallest AI. It converts text into natural, broadcast-quality speech at 44.1 kHz with sub-200ms first-chunk latency. The model is API-first — integrate via WebSocket, SSE, or standard HTTP. It supports 16 languages, instant and professional voice cloning, and context-aware emotional delivery that adjusts tone based on text content.
What is Lightning TTS and how does it work?
Lightning TTS is a real-time text-to-speech model built by Smallest AI. It converts text into natural, broadcast-quality speech at 44.1 kHz with sub-200ms first-chunk latency. The model is API-first — integrate via WebSocket, SSE, or standard HTTP. It supports 16 languages, instant and professional voice cloning, and context-aware emotional delivery that adjusts tone based on text content.
How does Lightning compare to ElevenLabs and Google TTS?
Lightning v3.1 scores 5.06 on WVMOS (audio quality) compared to ElevenLabs Turbo 2.5 at 4.64. Latency is under 200ms versus 250–300ms for ElevenLabs. Against Google Cloud TTS, Lightning offers higher fidelity output at 44.1 kHz native, a purpose-built architecture optimised for real-time voice agents, and a multilingual roadmap covering Indian languages that Google's standard voices don't support well. We published our full benchmark methodology — most competitors don't.
How does Lightning compare to ElevenLabs and Google TTS?
Lightning v3.1 scores 5.06 on WVMOS (audio quality) compared to ElevenLabs Turbo 2.5 at 4.64. Latency is under 200ms versus 250–300ms for ElevenLabs. Against Google Cloud TTS, Lightning offers higher fidelity output at 44.1 kHz native, a purpose-built architecture optimised for real-time voice agents, and a multilingual roadmap covering Indian languages that Google's standard voices don't support well. We published our full benchmark methodology — most competitors don't.
Is Hydra compliant for regulated industries like healthcare and finance?
Yes. Hydra is built with HIPAA, SOC 2 Type II, and PCI DSS compliance from the ground up — not retrofitted. We undergo annual third-party audits, maintain strict internal data governance, and offer on-premises deployment for teams that require their data to never leave their own infrastructure. Healthcare, debt collection, financial services, and legal are all supported use cases with the appropriate compliance documentation available upon request.
Is Hydra compliant for regulated industries like healthcare and finance?
Yes. Hydra is built with HIPAA, SOC 2 Type II, and PCI DSS compliance from the ground up — not retrofitted. We undergo annual third-party audits, maintain strict internal data governance, and offer on-premises deployment for teams that require their data to never leave their own infrastructure. Healthcare, debt collection, financial services, and legal are all supported use cases with the appropriate compliance documentation available upon request.
Is Lightning TTS HIPAA compliant?
Yes. Lightning TTS is HIPAA, SOC 2 Type II, PCI DSS, and GDPR compliant. We undergo annual third-party audits, maintain strict data governance, and offer on-premises deployment for teams that require data sovereignty. No synthesised audio is retained and no personal voice data is stored beyond the scope of voice cloning. Compliance documentation is available upon request.
Is Lightning TTS HIPAA compliant?
Yes. Lightning TTS is HIPAA, SOC 2 Type II, PCI DSS, and GDPR compliant. We undergo annual third-party audits, maintain strict data governance, and offer on-premises deployment for teams that require data sovereignty. No synthesised audio is retained and no personal voice data is stored beyond the scope of voice cloning. Compliance documentation is available upon request.
What industries and use cases is Lightning built for?
Lightning powers voice agents, IVR systems, audiobook generation, podcast production, gaming dialogue, accessibility tools, and any application where the voice is the product. Our enterprise customers span fintech (payment IVR), healthcare (appointment reminders, clinical agents), insurance (claims processing), travel (booking and support), telecom (digital-first support), and AI voice agent platforms that use Lightning as their TTS layer.
What industries and use cases is Lightning built for?
Lightning powers voice agents, IVR systems, audiobook generation, podcast production, gaming dialogue, accessibility tools, and any application where the voice is the product. Our enterprise customers span fintech (payment IVR), healthcare (appointment reminders, clinical agents), insurance (claims processing), travel (booking and support), telecom (digital-first support), and AI voice agent platforms that use Lightning as their TTS layer.
How quickly can I integrate the API?
Most developers generate their first audio in under 5 minutes. The API supports Python and JavaScript SDKs, plus direct cURL. Streaming options include WebSocket, Server-Sent Events, and standard HTTP. For teams on Twilio, Lightning drops in as a TTS layer replacement with no infrastructure changes required. Output formats include PCM, MP3, WAV, and mulaw at sample rates from 8kHz to 44.1kHz.
How quickly can I integrate the API?
Most developers generate their first audio in under 5 minutes. The API supports Python and JavaScript SDKs, plus direct cURL. Streaming options include WebSocket, Server-Sent Events, and standard HTTP. For teams on Twilio, Lightning drops in as a TTS layer replacement with no infrastructure changes required. Output formats include PCM, MP3, WAV, and mulaw at sample rates from 8kHz to 44.1kHz.
What languages are supported?
Lightning currently supports 16 languages: English, Hindi, Spanish, Tamil, Marathi, Bengali, Gujarati, Kannada, French, Hebrew, Italian, Arabic, Russian, German, Dutch, and Polish. Each language includes native accent support — not translations layered onto an English base model. Additional languages are continuously added to the roadmap based on enterprise demand.
What languages are supported?
Lightning currently supports 16 languages: English, Hindi, Spanish, Tamil, Marathi, Bengali, Gujarati, Kannada, French, Hebrew, Italian, Arabic, Russian, German, Dutch, and Polish. Each language includes native accent support — not translations layered onto an English base model. Additional languages are continuously added to the roadmap based on enterprise demand.
What languages are supported?
Lightning currently supports 16 languages: English, Hindi, Spanish, Tamil, Marathi, Bengali, Gujarati, Kannada, French, Hebrew, Italian, Arabic, Russian, German, Dutch, and Polish. Each language includes native accent support — not translations layered onto an English base model. Additional languages are continuously added to the roadmap based on enterprise demand.
What languages are supported?
Lightning currently supports 16 languages: English, Hindi, Spanish, Tamil, Marathi, Bengali, Gujarati, Kannada, French, Hebrew, Italian, Arabic, Russian, German, Dutch, and Polish. Each language includes native accent support — not translations layered onto an English base model. Additional languages are continuously added to the roadmap based on enterprise demand.
How does voice cloning work?
Lightning offers two voice cloning tiers. Instant cloning requires just 5–15 seconds of audio and produces a usable voice clone immediately — ideal for rapid prototyping and testing. Professional cloning requires 45+ minutes of high-quality audio and captures the full range of a speaker's intonation, accent, emotion, and vocal nuances — suitable for production use where fidelity matters. All cloning requires explicit consent from the voice owner.
How does voice cloning work?
Lightning offers two voice cloning tiers. Instant cloning requires just 5–15 seconds of audio and produces a usable voice clone immediately — ideal for rapid prototyping and testing. Professional cloning requires 45+ minutes of high-quality audio and captures the full range of a speaker's intonation, accent, emotion, and vocal nuances — suitable for production use where fidelity matters. All cloning requires explicit consent from the voice owner.
What does Lightning TTS cost?
New accounts receive $200 in free credits — enough to generate hours of audio. No credit card is required to start. Beyond the free tier, pricing scales with usage. Enterprise teams with high-volume or custom deployment needs can book a demo to discuss pricing structures tailored to their use case. We offer both cloud and on-premises deployment options.
What does Lightning TTS cost?
New accounts receive $200 in free credits — enough to generate hours of audio. No credit card is required to start. Beyond the free tier, pricing scales with usage. Enterprise teams with high-volume or custom deployment needs can book a demo to discuss pricing structures tailored to their use case. We offer both cloud and on-premises deployment options.
Your data, secure with Enterprise Security
Your data is secured by top SOC 2 Type 2, HIPAA, and PCI compliance standards, both in the cloud and on-premises.
We comply with HIPAA to protect your health information.
Smallest.ai has undergone SOC 2 Type II attestation and undergoes annual audits.
Strict internal audit processes for data management.
Infrastructure that meets ISO standards
Your data, secure with Enterprise Security
Your data is secured by top SOC 2 Type 2, HIPAA, and PCI compliance standards, both in the cloud and on-premises.
We comply with HIPAA to protect your health information.
Smallest.ai has undergone SOC 2 Type II attestation and undergoes annual audits.
Strict internal audit processes for data management.
Infrastructure that meets ISO standards
Your data, secure with Enterprise Security
Your data is secured by top SOC 2 Type 2, HIPAA, and PCI compliance standards, both in the cloud and on-premises.
We comply with HIPAA to protect your health information.
Smallest.ai has undergone SOC 2 Type II attestation and undergoes annual audits.
Strict internal audit processes for data management.
Infrastructure that meets ISO standards
The last TTS
model you'll need
Instant access
Instant access
$200 free credits
$200 free credits
SOC 2 Compliant
SOC 2 Compliant
Cancel anytime
Cancel anytime