Vapi Integration - API Setup

Connect your Vapi AI assistants to Vobiz SIP infrastructure using API/CLI commands.

Prefer using the Dashboard?

Check out the Dashboard Setup Guide for a visual step-by-step walkthrough.

Overview

This guide shows how to integrate Vapi with Vobiz programmatically to enable outbound calling - your AI assistants can call any phone number.

Call flow:

Integration Flow

Your App → Vapi API → Vobiz SIP → Phone Network → Person Answers → AI Assistant Speaks

Prerequisites

✓
Vobiz Account with SIP trunk → Create account
✓
Vapi Account with private key → Sign up
✓
Vapi Assistant created → Create in dashboard
✓
Phone number from Vobiz (optional, for caller ID)

Part 1: Vobiz Setup

Create SIP Trunk

Create a SIP trunk in Vobiz to handle voice traffic.

See: Vobiz SIP Trunks Documentation

Save these values from the response:

sip_domain (e.g., 5f3a607b.sip.vobiz.ai)
username
password

You'll need them for Vapi configuration.

Get Phone Number

Purchase a phone number for outbound caller ID or inbound calls.

See: Vobiz Phone Numbers Documentation

Part 2: Vapi Setup

Get Vapi Private Key

Log in to Vapi Dashboard
Click your profile icon (top right)
Go to Settings → API Keys
Click Create new key
Copy the key

Example Private Key

c07947df-6ba2-4e58-92f5-35e92849f6c2

Save this key - you'll use it in all API requests.

Get Assistant ID

In Vapi Dashboard, go to Assistants
Select your assistant (or create one)
Copy the Assistant ID

Example Assistant ID

9fb6d4c5-9403-49ea-afeb-9b493d63b474

Or list via API:

List Assistants

curl "https://api.vapi.ai/assistant" \
  -H "Authorization: Bearer YOUR_VAPI_PRIVATE_KEY"

Part 3: Connect Vobiz to Vapi (3 Steps)

Step 1: Create SIP Credential in Vapi

This registers your Vobiz SIP trunk with Vapi for outbound calling.

Create SIP Credential

curl -X POST "https://api.vapi.ai/credential" \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer YOUR_VAPI_PRIVATE_KEY" \
  -d '{
    "provider": "byo-sip-trunk",
    "name": "Vobiz Trunk",
    "gateways": [{
      "ip": "bfab10fb.sip.vobiz.ai",
      "inboundEnabled": false
    }],
    "outboundLeadingPlusEnabled": true,
    "outboundAuthenticationPlan": {
      "authUsername": "Vapi_user",
      "authPassword": "Password@123"
    }
  }'

Replace:

bfab10fb.sip.vobiz.ai → Your Vobiz SIP domain
Vapi_user → Your Vobiz username
Password@123 → Your Vobiz password

Response

{
  "id": "65a79bd2-c1b9-4c83-8e55-97c22c092b48",
  "provider": "byo-sip-trunk",
  "gateways": [{
    "ip": "bfab10fb.sip.vobiz.ai",
    "inboundEnabled": false
  }],
  ...
}

Save the `id` field - this is your Credential ID.

Step 2: Register Phone Number

This associates your phone number with the SIP credential for caller ID.

curl -X POST "https://api.vapi.ai/phone-number" \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer YOUR_VAPI_PRIVATE_KEY" \
  -d '{
    "provider": "byo-phone-number",
    "name": "Vobiz Line",
    "number": "08071387149",
    "numberE164CheckEnabled": false,
    "credentialId": "65a79bd2-c1b9-4c83-8e55-97c22c092b48"
  }'

Replace:

08071387149 → Your Vobiz phone number
65a79bd2-c1b9-4c83-8e55-97c22c092b48 → Your Credential ID from Step 1

Response

{
  "id": "91122039-9644-47fd-a545-d865075a6941",
  "number": "08071387149",
  "status": "active",
  "credentialId": "65a79bd2-c1b9-4c83-8e55-97c22c092b48",
  ...
}

Save the `id` field - this is your Phone Number ID.

Step 3: Make Outbound Call

Now you can make calls using your AI assistant!

Initiate Outbound Call

curl -X POST "https://api.vapi.ai/call/phone" \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer YOUR_VAPI_PRIVATE_KEY" \
  -d '{
    "assistantId": "9fb6d4c5-9403-49ea-afeb-9b493d63b474",
    "customer": {
      "number": "+919148223344",
      "numberE164CheckEnabled": false
    },
    "phoneNumberId": "91122039-9644-47fd-a545-d865075a6941"
  }'

Replace:

9fb6d4c5-9403-49ea-afeb-9b493d63b474 → Your Assistant ID
+919148223344 → Destination number to call
91122039-9644-47fd-a545-d865075a6941 → Your Phone Number ID from Step 2

Response

{
  "id": "019a0bce-0cf3-7337-a253-f65f4e9c68f4",
  "status": "queued",
  "type": "outboundPhoneCall",
  "assistantId": "9fb6d4c5-9403-49ea-afeb-9b493d63b474",
  "customer": {
    "number": "+919148223344"
  },
  "phoneNumberId": "91122039-9644-47fd-a545-d865075a6941",
  ...
}

Call initiated! The phone will ring, and when answered, your AI assistant will speak.

Verification

Check Call Status

View your call logs in Vapi Dashboard → Calls

Or via API:

Get Call Details

curl "https://api.vapi.ai/call/019a0bce-0cf3-7337-a253-f65f4e9c68f4" \
  -H "Authorization: Bearer YOUR_VAPI_PRIVATE_KEY"

Test Call Flow

Run Step 3 to initiate a call
Wait for destination phone to ring
Answer the call
AI assistant will greet and speak
Check call transcript in Vapi Dashboard

Troubleshooting

"Unauthorized" / "Invalid API Key"

Problem: Vapi Private Key is incorrect.

Fix:

Verify you copied the entire key
Generate new key at Vapi Dashboard → Settings → API Keys

"Couldn't Get Assistant"

Problem: Wrong Assistant ID or doesn't exist.

Fix:

Run: curl "https://api.vapi.ai/assistant" -H "Authorization: Bearer YOUR_KEY"
Use the correct id from the response
Don't confuse Credential ID with Assistant ID

"SIP Authentication Failed"

Problem: Vobiz credentials are incorrect.

Fix:

Verify SIP domain, username, password in Vobiz Console
Ensure you're using the exact sip_domain (e.g., bfab10fb.sip.vobiz.ai)
Don't use generic sip.vobiz.ai

"Insufficient Balance"

Problem: Vobiz account has no credits.

Fix:

Log in to Vobiz Console → Billing
Add funds (minimum ₹100 recommended)

Call Connects But Silent

Problem: Assistant configuration issue.

Fix:

Verify assistant has "First Message" configured in Vapi dashboard
Check assistant has voice provider set up
View call logs in Vapi Dashboard → Calls

Call Doesn't Connect

Problem: Wrong phone number format or trunk configuration.

Fix:

Use E.164 format: +919148223344 (with +)
Or local format: 09148223344 (without +)
Verify Vobiz trunk is active in Vobiz Console
Check Vobiz CDR logs for call attempts

Quick Reference

Required Credentials

What	Where to Get	Used In
Vapi Private Key	Vapi Dashboard → Settings → API Keys	All API requests
Vobiz SIP Domain	Vobiz Console → Trunks → sip_domain	Step 1: gateways[0].ip
Vobiz Username	Vobiz Console → Trunks → Username	Step 1: authUsername
Vobiz Password	Vobiz Console → Trunks → Password	Step 1: authPassword
Phone Number	Vobiz Console → Numbers	Step 2: number
Credential ID	Step 1 response → id	Step 2: credentialId
Phone Number ID	Step 2 response → id	Step 3: phoneNumberId
Assistant ID	Vapi Dashboard → Assistants → Assistant ID	Step 3: assistantId

Field Mapping: Vobiz → Vapi

Vobiz Field	→	Vapi Field	Step
sip_domain	→	gateways[0].ip	1
username	→	outboundAuthenticationPlan.authUsername	1
password	→	outboundAuthenticationPlan.authPassword	1
Phone number	→	number	2

API Endpoints

Action	Method	Endpoint
Create SIP Credential	POST	https://api.vapi.ai/credential
Register Phone Number	POST	https://api.vapi.ai/phone-number
Make Outbound Call	POST	https://api.vapi.ai/call/phone
List Assistants	GET	https://api.vapi.ai/assistant
Get Call Details	GET	https://api.vapi.ai/call/{callId}

All requests require:

Authorization: Bearer YOUR_VAPI_PRIVATE_KEY

Common Errors

Error	Cause	Fix
401 Unauthorized	Wrong Vapi Private Key	Verify key in dashboard
Assistant Does Not Exist	Wrong Assistant ID	List assistants via API
SIP auth failed	Wrong Vobiz credentials	Check Vobiz Console → Trunks
Insufficient balance	Low Vobiz credits	Add funds in Vobiz Console
Phone format error	Missing + or country code	Use +919148223344 or 09148223344

Complete Example

Here's a complete working example with real values from our setup:

Step 1: Create SIP Credential

curl -X POST "https://api.vapi.ai/credential" \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer c07947df-6ba2-4e58-92f5-35e92849f6c2" \
  -d '{
    "provider": "byo-sip-trunk",
    "name": "Vobiz Trunk 2",
    "gateways": [{
      "ip": "bfab10fb.sip.vobiz.ai",
      "inboundEnabled": false
    }],
    "outboundLeadingPlusEnabled": true,
    "outboundAuthenticationPlan": {
      "authUsername": "Vapi_user",
      "authPassword": "Password@123"
    }
  }'

# Response: Save credential ID
# {"id": "65a79bd2-c1b9-4c83-8e55-97c22c092b48", ...}

Step 2: Register Phone Number

curl -X POST "https://api.vapi.ai/phone-number" \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer c07947df-6ba2-4e58-92f5-35e92849f6c2" \
  -d '{
    "provider": "byo-phone-number",
    "name": "Vobiz Line 2",
    "number": "08071387149",
    "numberE164CheckEnabled": false,
    "credentialId": "65a79bd2-c1b9-4c83-8e55-97c22c092b48"
  }'

# Response: Save phone number ID
# {"id": "91122039-9644-47fd-a545-d865075a6941", ...}

Step 3: Make Outbound Call

curl -X POST "https://api.vapi.ai/call/phone" \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer c07947df-6ba2-4e58-92f5-35e92849f6c2" \
  -d '{
    "assistantId": "9fb6d4c5-9403-49ea-afeb-9b493d63b474",
    "customer": {
      "number": "+919148223344",
      "numberE164CheckEnabled": false
    },
    "phoneNumberId": "91122039-9644-47fd-a545-d865075a6941"
  }'

# Response: Call initiated!
# {"id": "019a0bce-0cf3-7337-a253-f65f4e9c68f4", "status": "queued", ...}

Inbound Call Setup

Receive inbound calls on your Vobiz number and route them to your Vapi AI assistant — all configured via API.

Inbound call flow:

Inbound Flow

Caller Dials Vobiz Number → Vobiz SIP → Vapi SIP Trunk → Vapi AI Assistant → Conversation

Step 1: Create Inbound SIP Credential in Vapi

Create a SIP trunk credential configured for inbound only — using the Vobiz gateway IP instead of a SIP domain.

Create Inbound SIP Credential

curl -X POST "https://api.vapi.ai/credential" \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer YOUR_VAPI_PRIVATE_KEY" \
  -d '{
    "provider": "byo-sip-trunk",
    "name": "Vobiz Inbound Trunk",
    "gateways": [{
      "ip": "13.233.44.61",
      "port": 5060,
      "netmask": 32,
      "inboundEnabled": true,
      "outboundEnabled": false
    }]
  }'

Response

{
  "id": "46deea29-645d-44a3-bf42-7c6ec2d4b65c",
  "provider": "byo-sip-trunk",
  "gateways": [{
    "ip": "13.233.44.61",
    "outboundEnabled": false
  }],
  "name": "Vobiz Inbound Trunk"
}

Save the id field — this is your Inbound Credential ID (also called Trunk ID).

Want both inbound and outbound on the same trunk? Add a second gateway entry for outbound with your Vobiz SIP domain and credentials:

Combined Inbound + Outbound

"gateways": [
  {
    "ip": "13.233.44.61",
    "inboundEnabled": true,
    "outboundEnabled": false
  },
  {
    "ip": "bfab10fb.sip.vobiz.ai",
    "inboundEnabled": false,
    "outboundEnabled": true
  }
]

Step 2: Get the Trunk ID

If you didn't save the ID from Step 1, retrieve it by listing all credentials:

List SIP Trunk Credentials

curl -X GET "https://api.vapi.ai/credential" \
  -H "Authorization: Bearer YOUR_VAPI_PRIVATE_KEY"

Find the entry with gateway IP: 13.233.44.61 and outboundEnabled: false. The id field is your Trunk ID.

Step 3: Configure Inbound Trunk in Vobiz

Create an inbound trunk in Vobiz Console that routes calls to Vapi:

Go to Vobiz Console → SIP Trunks → Inbound Trunk
Click Create New Trunk
Set Name, Transport: UDP
Set Primary URI to: <TRUNK_ID>.sip.vapi.ai
Example: 46deea29-645d-44a3-bf42-7c6ec2d4b65c.sip.vapi.ai
Link your Vobiz phone number to this trunk
Click Save

Or use the Vobiz API to create the inbound trunk programmatically. See SIP Trunks Documentation.

Step 4: Register Inbound Phone Number in Vapi

curl -X POST "https://api.vapi.ai/phone-number" \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer YOUR_VAPI_PRIVATE_KEY" \
  -d '{
    "provider": "byo-phone-number",
    "name": "Vobiz Inbound Line",
    "number": "+918071387376",
    "numberE164CheckEnabled": true,
    "credentialId": "46deea29-645d-44a3-bf42-7c6ec2d4b65c",
    "assistantId": "YOUR_ASSISTANT_ID"
  }'

Replace:

+918071387376 → Your Vobiz phone number
46deea29-... → Your Inbound Credential ID from Step 1
YOUR_ASSISTANT_ID → Your Vapi Assistant ID

Inbound Setup Complete!

Dial your Vobiz number — the call will route through to your Vapi AI assistant automatically.

Additional Resources

Vobiz Documentation

Vapi Documentation

Support

Vobiz: support@vobiz.ai
Vapi: Vapi Discord or support@vapi.ai

Integration complete!

Your Vapi assistants can now make outbound calls through Vobiz.

Next Steps:

Customize your assistant in Vapi Dashboard
View call logs and analytics in Vapi Dashboard
Build your voice AI application!

Vapi (Dashboard Setup)

Error Handling

Vapi Integration - API Setup

Overview

Prerequisites

Part 1: Vobiz Setup

Create SIP Trunk

Get Phone Number

Part 2: Vapi Setup

Get Vapi Private Key

Get Assistant ID

Part 3: Connect Vobiz to Vapi (3 Steps)

Step 1: Create SIP Credential in Vapi

Step 2: Register Phone Number

Step 3: Make Outbound Call

Verification

Check Call Status

Test Call Flow

Troubleshooting

"Unauthorized" / "Invalid API Key"

"Couldn't Get Assistant"

"SIP Authentication Failed"

"Insufficient Balance"

Call Connects But Silent

Call Doesn't Connect

Quick Reference

Required Credentials

Field Mapping: Vobiz → Vapi

API Endpoints

Common Errors

Complete Example

Inbound Call Setup

Step 1: Create Inbound SIP Credential in Vapi

Step 2: Get the Trunk ID

Step 3: Configure Inbound Trunk in Vobiz

Step 4: Register Inbound Phone Number in Vapi

Additional Resources

Vobiz Documentation

Vapi Documentation

Support

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