What is Bolna?
Bolna is a platform for building conversational Voice AI agents that can handle phone calls naturally, just like a human. Whether you’re automating customer support, qualifying leads, or scheduling appointments, Bolna provides the infrastructure to create, deploy, and scale voice agents.Build
Configure agents with prompts, voice, and tools
Deploy
Connect to phone numbers for inbound/outbound calls
Scale
Handle thousands of concurrent conversations
How Voice AI Works
Every conversation flows through a three-step pipeline that happens in real-time:Listen
Speech-to-Text (ASR) converts the caller’s voice into text that your AI can understand.Bolna supports Deepgram, Azure, ElevenLabs, and more.
Think
Large Language Model (LLM) processes the text, understands context, and generates an intelligent response.Connect OpenAI, Anthropic, Azure OpenAI, or your own LLM.
Speak
Text-to-Speech (TTS) converts the response into natural-sounding speech played back to the caller.Choose voices from ElevenLabs, Cartesia, Azure, and more.
Bolna orchestrates this entire pipeline in under 600ms, enabling natural, real-time conversations with minimal latency.
Key Terms Explained
New to Voice AI? Here’s what the technical terms mean in plain English:LLM (Large Language Model)
LLM (Large Language Model)
Think of it as: The brain of your AI agent.An LLM is an AI system (like ChatGPT) that understands language and generates human-like responses. When someone speaks to your agent, the LLM reads the transcribed text, understands what the person wants, and writes a response, just like a customer service rep would.Examples: OpenAI GPT-4, Anthropic Claude, Google Gemini
Transcriber / ASR (Speech-to-Text)
Transcriber / ASR (Speech-to-Text)
Think of it as: The ears of your AI agent.ASR (Automatic Speech Recognition) listens to what someone says on a call and converts their spoken words into written text. This text is then sent to the LLM so it can understand and respond.Examples: Deepgram, Azure Speech, Google STT
Synthesizer / TTS (Text-to-Speech)
Synthesizer / TTS (Text-to-Speech)
Think of it as: The voice of your AI agent.TTS (Text-to-Speech) takes the written response from the LLM and speaks it out loud in a natural-sounding voice. You can choose different voices, accents, and speaking styles to match your brand.Examples: ElevenLabs, Cartesia, Azure TTS
Telephony Provider
Telephony Provider
Think of it as: The phone company that connects your calls.A telephony provider handles the actual phone infrastructure for buying phone numbers, connecting calls, and ensuring audio quality. Bolna integrates with providers so your AI agent can make and receive real phone calls.Examples: Twilio, Plivo, Exotel, Vobiz
Agent
Agent
Think of it as: Your virtual employee.An agent is a complete Voice AI system configured with a personality, instructions, voice, and capabilities. It’s like hiring a virtual employee; you tell it what to say, how to act, and what tasks to perform.
Prompt
Prompt
Think of it as: The training manual for your agent.A prompt is a set of instructions you write to tell the agent how to behave. It includes the agent’s personality, what information to collect, how to handle different situations, and what NOT to say.
Latency
Latency
Think of it as: Response time, how fast the agent replies.Latency is the delay between when someone finishes speaking and when the agent starts responding. Lower latency (under 1 second) feels more natural, like a real conversation. Bolna optimizes for sub-600ms latency.
Knowledge Base / RAG
Knowledge Base / RAG
Think of it as: Reference documents your agent can read.A knowledge base is a collection of documents (PDFs, websites, FAQs) that your agent can search during conversations. RAG (Retrieval-Augmented Generation) is the technology that lets the agent find relevant information and use it in responses.
What Can Bolna Agents Do?
Handle Phone Calls
Inbound Calls
Answer customer calls 24/7 with AI-powered responses
Outbound Calls
Proactively reach customers for sales, reminders, and follow-ups
Batch Calling
Launch campaigns with thousands of concurrent calls
Call Transfer
Route to human agents when AI assistance isn’t enough
Execute Actions During Calls
Agents can perform real-time actions by calling external APIs and tools:Built-in Function Tools
Built-in Function Tools
| Tool | What It Does |
|---|---|
| Check Calendar Slots | Query available appointment slots via Cal.com |
| Book Appointments | Schedule meetings directly during the call |
| Transfer Calls | Route to human agents or other numbers |
| Custom Functions | Call any API endpoint based on conversation |
Extract Insights After Calls
Every conversation generates valuable data:Transcripts
Full conversation text with speaker labels
Recordings
Audio recordings for review and training
Summaries
AI-generated call summaries
- Customer intent and sentiment
- Key data points (name, email, order ID)
- Custom fields you define
Agent Configuration
Every Bolna agent is customized through 8 configuration tabs:- Core Settings
- Call Settings
Agent Tab
Prompts & PersonalityDefine your agent’s welcome message, instructions, and conversation behavior.
LLM Tab
Intelligence & KnowledgeChoose your language model and connect knowledge bases for context-aware responses.
Audio Tab
Voice & TranscriptionSelect voice provider, language, and transcription settings.
Engine Tab
Latency & BehaviorFine-tune response timing, interruption handling, and user detection.
Use Cases
Customer Support
Handle FAQs, troubleshoot issues, and escalate complex cases
Lead Qualification
Qualify inbound leads and schedule meetings with sales reps
Appointment Booking
Book, reschedule, and confirm appointments automatically
Recruitment
Screen candidates and schedule interviews at scale