By Sagar Shankaran, Founder of CallSphere
Bolna 0.10 wires LiteLLM, Deepgram, ElevenLabs, Twilio and Plivo into one OSS orchestrator. Deploy a full conversational voice agent in under 200 lines of YAML + Python.
Key takeaways
TL;DR — Bolna is an end-to-end OSS framework specifically for voice-driven LLM agents. Where Vocode and Pipecat give you primitives, Bolna gives you a YAML-driven assistant that wires STT, LLM (via LiteLLM — OpenAI/DeepSeek/Llama/Cohere/Mistral), TTS and telephony in one config.
A Bolna assistant that answers an inbound Twilio call, qualifies a real-estate lead via a structured prompt, and writes the result to Postgres via a webhook tool.
pip install bolna fastapi uvicorn psycopg2-binary.llama3.1:8b (we'll point LiteLLM at it).flowchart LR
PSTN[Caller] --> TW[Twilio]
TW -->|WSS| BOL[Bolna Orchestrator]
BOL --> DG[Deepgram STT]
BOL --> LL[LiteLLM -> Ollama]
BOL --> EL[ElevenLabs TTS]
BOL --> RD[(Redis state)]
BOL -->|webhook| API[Your API]
.env configuration```bash
TWILIO_ACCOUNT_SID=... TWILIO_AUTH_TOKEN=... DEEPGRAM_AUTH_TOKEN=... ELEVENLABS_API_KEY=... REDIS_URL=redis://localhost:6379/0
OPENAI_API_BASE=http://127.0.0.1:11434/v1 OPENAI_API_KEY=ollama ```
```python
Hear it before you finish reading
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import requests, json agent = { "agent_config": { "agent_name": "RealEstate Qualifier", "agent_type": "other", "agent_welcome_message": "Hi, this is the property concierge. Are you looking to buy, sell, or rent today?", "tasks": [{ "task_type": "conversation", "tools_config": { "input": {"format": "wav", "provider": "twilio"}, "output": {"format": "wav", "provider": "twilio"}, "transcriber": {"provider": "deepgram", "model": "nova-2", "language": "en", "stream": True, "endpointing": 500}, "synthesizer": {"provider": "elevenlabs", "model": "eleven_turbo_v2", "stream": True, "voice_id": "EXAVITQu4vr4xnSDxMaL"}, "llm_agent": {"provider": "openai", "model": "llama3.1:8b", "max_tokens": 200, "temperature": 0.4, "extra_config": {"base_url": "http://127.0.0.1:11434/v1"}} }, "task_config": {"hangup_after_silence": 12, "ambient_noise": "office"} }], "agent_prompts": {"system_prompt": "Qualify the caller in 4 questions: intent, budget, timeline, contact. " "When done, call the webhook tool 'save_lead' with the JSON payload, then politely end the call."} } } r = requests.post("http://127.0.0.1:5001/agent", json=agent) print(r.json()) ```
```python agent["agent_config"]["tasks"][0]["tools_config"]["api_tools"] = [{ "name": "save_lead", "description": "Save the qualified lead to CRM.", "url": "https://your.api/leads", "method": "POST", "param_schema": {"type":"object","required":["intent","budget","timeline","contact"], "properties":{"intent":{"type":"string"},"budget":{"type":"string"}, "timeline":{"type":"string"},"contact":{"type":"string"}}}}] ```
Bolna will call this URL with the agent's structured output as the JSON body when the LLM emits the tool.
```bash docker compose up -d # bolna server, redis ```
docker-compose.yml from the repo wires the Python server, Twilio bridge, and Redis. Hit POST /agent to register your config from Step 2.
```python import requests r = requests.post("http://127.0.0.1:5001/call", json={ "agent_id": "<id from step 2>", "recipient_phone_number": "+15551234567", "from_number": "+18885550000" # Your Twilio DID }) ```
The recipient phone rings; Bolna handles the rest.
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```python r = requests.get(f"http://127.0.0.1:5001/executions/{execution_id}").json() for turn in r["transcript"]: print(turn["role"], "→", turn["content"]) ```
llama3.1:8b works only if you've set OPENAI_API_BASE to Ollama; otherwise LiteLLM tries OpenAI's catalog.CallSphere runs 37 specialist agents in 6 verticals on a tighter-coupled stack (OpenAI Realtime + ElevenLabs + Pion WebRTC + Postgres). Bolna is a great open alternative for teams that want the YAML-config experience and a self-hostable LiteLLM gateway. Healthcare uses 14 HIPAA tools on FastAPI :8084; OneRoof's 10 property specialists are a perfect parallel to the qualifier agent above. Flat $149/$499/$1499 · 14-day trial · 22% affiliate · /industries/real-estate.
Bolna vs Vocode? Bolna is config-driven; Vocode is code-driven.
Plivo support? Yes — swap twilio for plivo under tools_config.input.provider.
Local TTS? Set synthesizer.provider to coqui or piper (community plugins).
Multi-language? Deepgram nova-2-multi + ElevenLabs multilingual.
Latency? ~700–900 ms in our tests with Ollama on the same box.
Written by
Sagar Shankaran· Founder, CallSphere
Sagar Shankaran is the founder of CallSphere, where he builds production AI voice and chat agents deployed across healthcare, hospitality, real estate, and home services. He writes about agentic AI, LLM engineering, and shipping voice agents that handle real calls in production.
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