Smallest.ai pricing for text to speech: what a phone voice agent pays
As on 17 September 2026, Smallest.ai lists its Lightning V3.1 text to speech model at $0.175 per 10,000 characters and Lightning V3.1 Pro at about $0.195 per 10,000 characters on the Pay as you go plan, billed in US dollars per character generated. Enterprise pricing is custom. On Convo360 you add your own Smallest.ai key and pay Smallest.ai directly, with zero markup.
Prices as on 17 September 2026. Figures were checked against the provider's official pages on that date. Providers change prices and rules without notice, so confirm on the official page before you budget. Convo360 adds no markup: you pay the provider directly with your own account. Convo360 is not affiliated with Smallest.ai. Smallest.ai, Lightning and other product names are trademarks of their owner. Prices were read from Smallest.ai's official pages on 17 September 2026 and may change; always confirm on the official pricing page.
- Smallest.ai bills text to speech per character generated, in US dollars, not per API call or per minute.
- As on 17 September 2026 the Pay as you go rates are $0.175 per 10,000 characters for Lightning V3.1 and about $0.195 for Lightning V3.1 Pro.
- Lightning v3.1 lists trained voices in Hindi, Tamil, Kannada, Marathi, Telugu, Odia, Punjabi, Malayalam, Gujarati and Bengali, plus English and Spanish.
- Check that your language is enabled on your own Smallest.ai account, because Convo360 falls back to English if it is not.
- Convo360 adds zero markup: your Smallest.ai key goes in Settings → Provider Keys and you choose the voice on the agent.
Smallest.ai text to speech prices as on 17 September 2026
These figures were read from Smallest.ai's official model pricing page on 17 September 2026. Smallest.ai publishes prices in US dollars. The table covers only the text to speech rows a phone voice agent uses; the full list is on Smallest.ai's pricing page.
| Item | Pay as you go | Enterprise Plan |
|---|---|---|
| Lightning V3.1 | $0.175 per 10,000 characters | Custom |
| Lightning V3.1 Pro | about $0.195 per 10,000 characters | Custom |
| Concurrency for text to speech | 15 concurrent streams | Custom |
| Monthly character cap | 450M characters per month | Custom |
| Requests per minute for text to speech APIs | 100 | Custom |
Smallest.ai's docs state that Lightning v2 is deprecated and that new integrations should use Lightning v3.1 or Lightning v3.1 Pro. One caution: the Lightning v3.1 Pro model card in the docs lists a concurrency of 10 on the standard plan, while the pricing page shows 15. Confirm the limit in your Smallest.ai dashboard.
No monthly subscription tiers appear on the official pricing pages as on this date. Convo360 is not affiliated with Smallest.ai. Prices can change at any time, and the Smallest.ai page is the final word.
What you are actually billed for
The pricing FAQ on Smallest.ai's site says API usage is billed in US dollars, per model, and that you pay only for what you use. Text to speech is billed per character, speech to text per minute.
- Unit: Smallest.ai says both Lightning v3.1 and v3.1 Pro charge on the characters synthesized, not per API call. Only the text your agent speaks is counted.
- Chunking does not change the bill. The model card gives a maximum of 250 characters per request. A long reply is sent in pieces, but the charge follows the characters, not the number of pieces.
- Free credits: Smallest.ai's pricing page advertises $10 in free credits on the Pay as you go plan, with no commitments or long-term contracts. Confirm at signup how the credits apply to text to speech.
- Voice cloning: the pricing FAQ says cloning runs on standard Lightning v3.1 from 5 to 15 seconds of audio and is not available on the Pro pool. The detailed table on the same page shows voice cloning as No under Pay as you go. We could not verify a cloning price, so check your account before planning around a cloned voice.
Smallest.ai's pricing pages do not mention GST or any other tax, so check your first invoice.
The same site also lists per-minute prices for voice agents built on Smallest.ai's own agent platform. Those do not apply when you use only the text to speech API through Convo360.
A characters-per-call cost formula
The numbers below are ILLUSTRATIVE. Replace them with figures from your own call logs.
Formulas
- Characters per call = number of agent replies × average characters per reply
- Voice cost per call = characters per call ÷ 10,000 × published rate
- ₹ cost = USD amount × your bank's rate on the day + GST and forex fees, if any
Illustrative call: a 3-minute order confirmation where the agent speaks 12 replies of about 125 characters each, which is 1,500 characters.
| Model | Calculation | Per call | Per 1,000 calls |
|---|---|---|---|
| Lightning V3.1 | 1,500 ÷ 10,000 × $0.175 | about $0.026 | $26.25 |
| Lightning V3.1 Pro | 1,500 ÷ 10,000 × $0.195 | about $0.029 | $29.25 |
Count characters on real replies in the language you will use, not on an English draft, since a Hindi or Tamil sentence has a different character count.
This is only the voice line of the call. Telephony minutes, speech understanding and the AI brain are billed separately by those providers. For the whole picture, see AI voice agent cost per minute in India.
Indian language support, per Smallest.ai's docs
The Lightning v3.1 model card lists 12 languages with trained voices: English, Hindi, Tamil, Spanish, Kannada, Marathi, Telugu, Odia, Punjabi, Malayalam, Gujarati and Bengali. Eight European languages are routed through English or Hindi voices, and an auto setting detects the language. The card counts 217 voices.
For Lightning v3.1 Pro, the official pages differ. The pricing FAQ describes Pro as a curated, higher-quality pool that is English and Hindi only, while the Pro model card in the docs lists a wider set that includes nine Indic languages. Treat Pro coverage beyond English and Hindi as something to test, not assume.
On speed, Smallest.ai's pricing page claims sub 100ms time-to-first-audio. Its model cards give 200 ms time to first byte at 40 concurrent requests, measured in-region, and note that network latency adds on top. These are Smallest.ai's own figures, so judge latency on a real call.
Important for Convo360 users: language availability can depend on your Smallest.ai account. If Smallest.ai does not have the agent's language enabled for your account's region, Convo360 shows a warning on the agent and falls back to English so the call does not go silent. Preview the voice in your language first. If it fails, ask Smallest.ai support to enable the language, or choose another voice provider for that agent.
How to add your Smallest.ai key in Convo360
Convo360 is BYOK. You bring your own Smallest.ai account, Smallest.ai bills you directly, and Convo360 adds zero markup on characters or minutes. AI voice calls are part of the Pro plan at ₹2,999 per month, excluding 18% GST.
- Create a Smallest.ai account and generate an API key in its console.
- In Convo360, open Settings → Provider Keys, choose Smallest.ai and paste the key. Keys are encrypted at rest.
- Open your voice AI agent, select Smallest.ai as the voice and set the agent's language.
- Pick a voice from the ready-made list. Each voice has a play button, so you choose by listening and never type a voice ID.
- Place a test call to your own phone and listen in the language your customers speak.
The Smallest.ai key powers only the agent's spoken voice. Hearing the caller and thinking run on your own OpenAI or Gemini key, billed by that provider. If you have cloned a voice, it appears in the same picker from your Voice Library.
If the key is wrong or the account runs out of balance, Smallest.ai starts returning errors. Convo360's Provider Health monitoring detects this and shows a clear alert, so you know the fix is on the provider account and not in your flow. Setup details are in the voice docs.
Ways to keep the Smallest.ai bill down
Because the unit is the character, every saving comes from speaking fewer characters.
- Shorter replies. Tell the agent in its system prompt to answer in one or two short sentences. A 120-character reply costs half of a 240-character one.
- Do not re-synthesise fixed lines. A greeting or disclaimer that never changes can be recorded once and played with the Play Audio voice block.
- Send long details on WhatsApp. Addresses, payment links and price lists are slow to hear and cost characters. Let the agent say it is sending them, then send a message.
- Know the rate you picked. On the published list the two Lightning models differ by about $0.02 per 10,000 characters. Listen to both in your language before deciding which to run at volume.
- Check your telephony provider's inbound rate. Incoming call charges vary by provider and plan — for example, Plivo lists an India inbound rate and Exotel bills incoming calls at your plan's rate — so confirm the current price list before assuming inbound is free.
Still comparing voices? Read Indian voices for AI calls, then test on a real phone line.
Example conversation
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Frequently asked questions
Is there a free tier on Smallest.ai?
Smallest.ai's pricing page, as read on 17 September 2026, advertises $10 in free credits on its Pay as you go plan, with no commitments or long-term contracts. It does not list a permanent free tier, so confirm at signup how the credits apply to text to speech.
Is Smallest.ai text to speech billed per minute or per character?
Per character. Smallest.ai's pricing FAQ says both Lightning v3.1 and v3.1 Pro charge on the characters synthesized, not per API call. To estimate a per-minute figure, count the characters your agent speaks in a typical minute of your own calls and apply the formula.
Is GST extra on Smallest.ai prices?
Smallest.ai's pricing pages, as read on 17 September 2026, list prices in US dollars and say nothing about GST or any other tax. We could not verify the tax treatment, so check your first invoice or ask Smallest.ai support before fixing a budget.
Does Smallest.ai support Hindi and regional Indian languages?
The Lightning v3.1 model card lists trained voices in Hindi, Tamil, Kannada, Marathi, Telugu, Odia, Punjabi, Malayalam, Gujarati and Bengali, plus English and Spanish. Availability can depend on your account, so preview your language first. Convo360 falls back to English if it is not enabled.
What is the Smallest.ai price in rupees?
Smallest.ai publishes prices in US dollars only. To estimate rupees, multiply the USD amount by your bank's exchange rate on the day and add any forex fee or tax that applies. We do not quote a converted figure because the rate changes every day.
Can I use my own Smallest.ai account with Convo360?
Yes, that is how it works. Convo360 is BYOK, so you paste your own Smallest.ai API key under Settings → Provider Keys, select a Smallest.ai voice on the voice agent, and Smallest.ai bills your account directly with zero markup from Convo360.
Official sources
- Smallest.ai: Model pricing, Lightning TTS and Pulse STT (official)
- Smallest.ai: Voice agent pricing, Pay as you go (official)
- Smallest.ai docs: Models overview (official)
- Smallest.ai docs: Lightning v3.1 model card (official)
- Smallest.ai docs: Lightning v3.1 Pro model card (official)
- Smallest.ai: Lightning text to speech product page (official)
Related reading
Available across India — see WhatsApp & AI calling automation by state and city.