The telephony API for AI agents.
Bring the agent you already built. Tone gives it a +91 number, streams the call audio to it over a WebSocket, and runs the TRAI compliance around every call.
Talk to your own agent from the dashboard — test keys are free.
Plugs into the stack you already run.
Agents act mid-call — book a slot, look up an order, send a payment link — through the tools your team already uses. Anything with an HTTP API works today.
- Cal.comScheduling
- HubSpotCRM
- SalesforceSoonCRM
- LeadSquaredCRM
- Zoho CRMSoonCRM
- Google CalendarSoonScheduling
- ShopifyCommerce
- Google SheetsSoonData
- WhatsAppMessaging
- SMSMessaging
- WATIMessaging
- AiSensyMessaging
- SlackMessaging
- n8nAutomation
- MakeAutomation
- ZapierAutomation
- Signed webhooksEvery call event
- SarvamSpeech
- MurfVoices
- CartesiaVoices
- Google GeminiLLM
- Azure OpenAILLM
- AWS BedrockLLM
- Your agentover WebSocket
- Any HTTP APIDescribe it once
Built for production voice AI, from number to evidence.
The phone number, the regulation around the call, the call itself and the record of it — one API, one bill.
+91 numbers over an API.
Search, buy and route Indian numbers across carriers — with 140 and 160 series on request — then dial out or answer on them, from the API or a campaign.
- +91 22 4xxx 1170Mumbai · landlineactive
- +91 98xxx x4402Pan-India · mobileactive
- 1800 xxx xxxxPan-India · toll-freeactive
- +91 140 xxx xxxxPromotional · 140 serieson request
- +91 160 xxx xxxxService · 160 serieson request
Checked before every dial.
Six checks run before a carrier is asked to ring anyone. A check that fails stops the dial, and the refusal is sealed into your evidence like any call.
- dltheader registered
- a2pauto-dialer declared
- time_window14:05 IST · 09:00–21:00
- dncnot suppressed
- dnd_registernot listed
- consentexplicit, on record
Every call graded.
After every call, an AI judge checks it against the questions you set, says why for each answer, and pulls out the details you asked for.
- Did the customer confirm the order?Said “हाँ, गुरुवार ठीक है” when asked.Pass
- Was the delivery address confirmed?Agreed to 14, MG Road, Indiranagar.Pass
- Was a cancellation reason captured?Not needed — the order went ahead.Unclear
Outcomes, pushed to your stack.
The moment a call ends, Tone sends the result to your system — summary, transcript, recording and the details your agent collected. If your server is down it retries, and anything missed can be fetched again.
- Priya confirmed her COD ordercall.completed · order_confirmed: true200 · 84 ms
- Karthik moved his appointmentcall.completed · preferred_time: Sat 10:00200 · 71 ms
- Rahul didn’t pick upcall.failed · disposition: no_answer503 → retried · 200
- Diwali reminder campaign finishedcampaign.completed · 1,240 calls200 · 96 ms
Built for developers, ready for business.
Conversations that don't wait.
quality on every call recordTone listens, thinks and speaks at once — and stops the moment it is interrupted.
01The caller asks a question
Their voice streams in from the phone line.
Production-ready capabilities.
What a team calling Indian customers at volume needs on day one — not after the first complaint.
TRAI-compliant by default
Calling windows, Do-Not-Call, the DND register, consent and the AI disclosure — enforced server-side on every call, never left to a prompt.
Campaigns at scale
Upload a list, pace the dialling, retry the no-answers, and check promotional lists against the DND register before launch.
Bring your own carrier
Point your carrier or PBX at Tone's SIP gateway and keep your numbers. Enabled per account on request.
Live and test keys
tone_test_ keys run the whole flow against magic numbers, for free. Going live is a key swap.
Encrypted and signed
Secrets encrypted at rest, every webhook HMAC-signed, and phone numbers masked in our logs.
GST invoices, automatically
A prepaid wallet in rupees, with a GST tax invoice issued for every top-up.
Two plans. Both pay as you go.
Prepaid, per second, no subscription. Rates exclude GST. Test mode is always free.
Developer
Sign up and place calls today. Pay as you go, billed per second.
Start free in test mode- Every voice, language and model
- The full compliance gate
- Recordings, transcripts and webhooks
- Numbers from ₹299/month
Enterprise
A rate agreed for your organization, discounted further at higher volume.
Talk to sales- Everything in Developer
- A per-minute rate agreed for you
- Lower rates as your volume grows
- Your own SIP trunk, on request
Your own agent ₹2.00/min · your own SIP trunk ₹4.50/min · compliance API ₹0.10/verdict
Full pricing and an estimatorHow this actually works.
Measured numbers, the regulation stated plainly, and what automated calling is really used for in India.
How a voice AI pipeline actually works, end to end
What happens between a caller finishing a sentence and an agent answering it: voice activity detection, streaming speech recognition, the language model, speech synthesis, and the four places it usually breaks.
Read articleTCCCPR for AI voice calling: what the rules say, and five things vendors get wrong
India's telemarketing regulation, read from the gazette text rather than from vendor blogs — the number series, the pre-declaration duty, the calling window, and the rules that do not exist.
Read articleVoice AI latency in India: the numbers we measure in ap-south-1
A stage-by-stage latency breakdown of a production voice agent running in Mumbai — where every millisecond of a 1,220ms reply goes, and why in-region matters more than model choice.
Read articleStop fighting telecom APIs.
Start building AI.
+91 numbers, TRAI compliance and a realtime voice pipeline behind one API — built for voice agents that call India.
Pay as you go from ₹4.00 per connected minute. Test keys are free.