AI voice agent platform
An AI voice agent platform is software for building, deploying and monitoring voice agents: AI programs that hold spoken conversations with people, usually over the phone. It connects speech-to-text, a large language model and text-to-speech to phone numbers, so the agent can answer calls, place calls and take actions while it talks.
What is an AI voice agent platform?
On Bolna, every agent follows the same lifecycle. You build it by setting the prompt, LLM, voice, languages, tools and knowledge base. You deploy it to a phone number, a batch campaign or a web page. Then you monitor each call through recordings, transcripts, webhooks and the structured data the agent extracts from the conversation.
More than 1,000 companies use Bolna. Agents speak 20+ languages, including Hindi, Hinglish, Tamil and Telugu, and a single agent can switch languages mid-call when the caller does.
You can start from a ready-made template in the library of voice agents or build one from scratch.
How a Bolna voice agent handles a call
The caller speaks
A transcriber (speech-to-text) turns the caller's audio into text. Bolna supports Deepgram, Azure, ElevenLabs and other transcription providers.
The LLM decides what to say
A large language model reads the transcript with your prompt and knowledge base and writes the reply. You can connect OpenAI, Anthropic, Azure OpenAI or your own model. If the reply needs data, the model calls one of the tools you gave it.
The agent answers out loud
A synthesizer (text-to-speech) turns the reply into audio with the voice you picked, from providers such as ElevenLabs, Cartesia and Azure. You can also clone or import your own voice.
The call is logged
When the call ends you get the recording, transcript, cost and latency for that call, plus any fields you asked the agent to extract, such as intent, an order ID or a callback time.
You choose the provider for each step. See the speech-to-text, LLM and text-to-speech integrations, or read how Bolna works in the docs.
AI phone agents for inbound and outbound calls
An AI phone agent is a voice agent connected to a phone number. Every Bolna agent can answer and place phone calls, and you decide which numbers and carrier it uses.
Inbound calls
Assign a phone number to an agent and it answers every call to that number. It can identify the caller, route them through an IVR menu, and transfer the call to a person. Inbound calls have no concurrency limit and are never queued.
Outbound calls
Start one call from the dashboard or the API, or upload a CSV and call a whole list as a batch. Paid accounts start at 10 concurrent outbound calls, and calls above the limit wait in a queue instead of failing.
Phone numbers
Buy a dedicated number from the Bolna dashboard for $5 a month. US numbers come through Twilio, and Indian numbers through Plivo or Vobiz. Bolna also sells regulated 140 and 160-series numbers for India.
Your own telephony
Connect your own Twilio account for calls outside India, or Plivo, Exotel or Vobiz for calls within India. Or bring your own SIP trunk: any carrier that speaks standard SIP works, and your numbers and rates stay with your carrier.
Compare carriers on the telephony integrations page, or follow the docs to receive inbound calls, make outbound calls or connect a SIP trunk.
What the platform includes
Ways to build a voice agent on Bolna
Agent Studio
Fill in a three-step form with the call goal, conversation flow and closing line, or upload a script or FAQ document. Studio writes the prompt, picks a voice and publishes the agent.
Graph agents
Split the call into nodes such as greet, qualify, collect and confirm, each with its own instructions and rules for moving to the next step.
REST API
Create agents, place calls and pull transcripts from your own backend. An agent made in the dashboard can be edited over the API, and the reverse.
No-code tools
Trigger calls from a spreadsheet or CRM event with Make.com, n8n, Zapier, viaSocket or Google Sheets.
Voice agents teams run on Bolna
Customer support
Answer support calls at any hour and hand harder cases to a person.
Lead qualification
Call new leads, ask your qualifying questions and pass the ready ones to sales.
Front desk
Pick up the main line, answer common questions and book appointments.
Recruitment screening
Phone-screen applicants by asking every candidate the same questions.
Browse all voice agents or check Bolna pricing.
Frequently asked questions
An AI voice agent platform is software for building and running voice agents that talk to people over the phone or in the browser. It handles speech-to-text, the language model, text-to-speech and the phone connection, so you only write what the agent should say and do. Bolna is one such platform.
An AI phone agent is a voice agent connected to a phone number. It answers incoming calls or places outgoing ones and holds the conversation itself. On Bolna it can also transfer the caller to a person, book a meeting or call your API during the call.
Pay-as-you-go starts at $0.06 per minute (about ₹5.52), with speech-to-text, the LLM and text-to-speech included when the agent uses the bundled models. Telephony and the platform fee are added per minute, and every new account gets $5 in free credits. You can also bring your own LLM, TTS and ASR keys to lower the cost.
20+ languages, including Hindi, Hinglish, Tamil and Telugu. The language list also includes French, Spanish, Dutch, Indonesian and Malay. An agent can detect when the caller switches between English and ten Indian languages and follow them mid-call.
Yes. Connect your own Twilio, Plivo, Exotel or Vobiz account, or bring your own SIP trunk from any standard SIP carrier, and the agent answers and places calls on your numbers. You can also buy a US or Indian number from Bolna for $5 a month.
With Auto Build in Agent Studio, you describe the use case in a three-step form and get a call-ready agent in 5 to 8 minutes. You can then edit every setting in the agent builder or over the API.
Yes. Bolna agents use function tools that follow the OpenAI function-calling format. Built-in tools check open slots and create bookings in Cal.com, transfer the call and search the web, and a custom function can call any HTTP endpoint with values collected from the caller.
Build your first voice agent
Talk through your call flow with the Bolna team, or start in Agent Studio with $5 in free credits.