> ## Documentation Index
> Fetch the complete documentation index at: https://www.vobiz.ai/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# Vobiz vs Vapi — Telephony Infrastructure vs Voice AI Platform

> Vapi is an AI voice agent platform. Vobiz is telephony infrastructure. They work together — Vapi connects to Vobiz for SIP trunking and phone numbers. How they fit together and when to use each.

## Vobiz vs Vapi: Different Layers of the Stack

Vobiz and Vapi are at different layers of the AI voice stack. Vapi is an AI voice agent orchestration platform — it manages LLM selection, TTS, STT, conversation flow, and the agent API. Vobiz is telephony infrastructure — it provides the SIP trunk, phone numbers, outbound calling, inbound routing, AMD, and real-time audio streaming.

**They complement each other.** Vapi's recommended way to place and receive PSTN calls is to connect a SIP trunk from a provider like Vobiz. If you're evaluating Vobiz as a Vapi telephony provider, that's the right comparison. If you're looking to replace Vapi's orchestration capabilities, Vobiz alone covers different use cases.

## What each platform does

| Layer | Vapi | Vobiz |
| - | - | - |
| **LLM (conversation logic)** | ✓ Any provider | — |
| **TTS (voice synthesis)** | ✓ Multiple providers | — |
| **STT (transcription)** | ✓ Managed | — |
| **Agent configuration API** | ✓ | — |
| **Squad / multi-agent calls** | ✓ | — |
| **SIP trunking (PSTN)** | Requires external provider | ✓ |
| **Phone numbers** | Limited built-in US | ✓ 130+ countries |
| **India 140-series numbers** | Not available | ✓ |
| **AMD (answering machine detection)** | Via SIP trunk | ✓ Per-call |
| **WebSocket audio streaming** | ✓ | ✓ Bidirectional |
| **XML call control** | — | ✓ |
| **Call recordings** | — | ✓ |
| **INR billing + GST invoice** | ✗ | ✓ |
| **Self-serve signup** | ✓ | ✓ |

## How they work together

Vapi connects to Vobiz as its SIP trunk provider. Vobiz handles the PSTN connection; Vapi handles the AI agent.

```
Incoming PSTN call
        │
        ▼
   Vobiz SIP trunk + number
        │  (SIP INVITE to Vapi)
        ▼
   Vapi agent
   ├── STT → LLM → TTS pipeline
   └── Conversation flow logic
        │  (audio back over SIP)
        ▼
   Caller hears the AI response
```

For outbound calls, Vapi calls the Vobiz REST API (or uses the Vapi outbound call API with Vobiz as the provider) to place the call. Vobiz dials the number, runs AMD, and connects the answered call to the Vapi agent session.

See the [Vapi + Vobiz integration guide](https://www.vobiz.ai/docs/integrations/vapi-api.md) for the full setup, or the [Vapi dashboard integration](https://www.vobiz.ai/docs/integrations/vapi-dashboard.md) for UI-based configuration.

## When to use Vapi + Vobiz

Use Vapi as your orchestration layer and Vobiz as your telephony layer when:

* You want a managed agent API with structured conversation flows, squads, and analytics
* You need to swap LLM and TTS providers without rebuilding your stack
* You want pre-built call analysis and transcript tooling
* Your Vapi deployment needs PSTN calling outside the US (Vobiz covers 130+ countries)
* You need India 140-series numbers for TRAI-compliant A2P outbound

## When to use Vobiz alone

Vobiz handles voice AI without Vapi as the orchestration layer. Use Vobiz directly when:

* You are building a custom AI pipeline (your own STT, LLM, TTS, conversation logic)
* You want to mix traditional IVR (XML) with AI segments in the same call
* You are using an orchestration layer other than Vapi (Retell AI, Pipecat, LiveKit, ElevenLabs)
* You need maximum control over audio format, streaming rate, and latency

```xml Example: mixing IVR and AI in one call theme={null}
<?xml version="1.0" encoding="UTF-8"?>
<Response>
    <Gather action="/handle-menu" numDigits="1">
        <Speak>Press 1 for sales, 2 for support.</Speak>
    </Gather>
</Response>
```

```xml After the caller selects support: theme={null}
<?xml version="1.0" encoding="UTF-8"?>
<Response>
    <Stream bidirectional="true" keepCallAlive="true">
        wss://your-ai-agent.com/support-stream
    </Stream>
</Response>
```

## Pricing comparison

| | Vobiz | Vapi |
| - | - | - |
| **Model** | Pay-as-you-go telephony | Per-minute AI + telephony bundled |
| **Voice rate (India)** | ₹0.45/min | USD-denominated; varies by plan |
| **Phone numbers** | Per number per month | Limited US numbers included |
| **Global numbers** | ✓ 130+ countries | Via SIP trunk only |
| **Free tier** | 3 concurrent calls + signup credits | Trial minutes |
| **Billing** | INR with GST invoice | USD |

When using Vapi + Vobiz, you pay Vapi for agent minutes (LLM tokens + TTS + orchestration) and Vobiz separately for telephony minutes and number rental. The invoices are separate.

## India support

| | Vobiz | Vapi |
| - | - | - |
| **India phone numbers** | ✓ DID, 140-series | ✗ |
| **India outbound** | ✓ Direct carrier interconnects | Depends on SIP trunk |
| **140-series caller ID (TRAI)** | ✓ | ✗ |
| **INR billing** | ✓ | ✗ |
| **GST invoice** | ✓ | ✗ |
| **India latency** | PoPs in Mumbai region | Depends on SIP trunk |

For India deployments, Vobiz is essential regardless of which AI orchestration platform you choose. Vapi cannot provision Indian numbers or 140-series caller IDs — the telephony compliance layer must come from a provider like Vobiz.

## Developer experience

| | Vobiz | Vapi |
| - | - | - |
| **Call creation** | REST API + SIP | REST API |
| **Agent configuration** | XML webhooks + streaming | JSON agent config |
| **Audio interface** | WebSocket bidirectional | WebSocket |
| **Docs quality** | Full API reference + examples | Full API reference + examples |
| **Time to first call** | \< 5 minutes | \< 5 minutes |
| **Self-serve** | ✓ | ✓ |

## Summary

| Use case | Recommendation |
| - | - |
| Need a managed agent API + dashboard | Vapi + Vobiz for telephony |
| Need India 140-series numbers | Vobiz (required) |
| Building a custom AI pipeline | Vobiz alone |
| Calling in 130+ countries | Vobiz (Vapi's built-in numbers are US-limited) |
| Switching SIP trunk provider for existing Vapi setup | Switch to Vobiz |
| Replacing Vapi's orchestration layer | Different orchestration layer + Vobiz |


This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.