Vapi

From VoIP.ms Wiki

Latest revision as of 16:26, 5 February 2026

Vapi is a platform for building, testing, and deploying voice AI agents. It provides the infrastructure necessary for businesses to create custom voice assistants that can handle call operations for existing customer support, appointment booking, and sales calls, or for building new products using voice AI like prior authorization and product onboarding assistants.

For more details or to sign up to Vapi, visit: Vapi.api

VoIP.ms Sub Account configuration

To register a SIP trunk in Vapi you will need a Sub Account. To create one, in your VoIP.ms Customer Portal go to Sub Accounts >> Create Sub Account.

Creating a Sub Account for Vapi

Use these parameters for the Sub Account:

1.1 Protocol: SIP

1.2 Authentication type: Static IP Authentication

1.3 Username: Any name of your choice (E.g. 100000_Vapi)

1.4 IP Address or Fully Qualified Domain Name: sip.vapi.ai (Use this for now, we will have to add an UUID generated by Vapi later)

1.5 Device type: Asterisk, IP PBX, Gateway or VoIP Switch

1.6 CallerID Number: I use a system capable of passing its own CallerID.

1.7 Click on Create Account.

 All the settings not mentioned can be left with the default values or be adjusted according to your use-case needs.

Vapi configuration

To use Vapi with VoIP.ms you will need to add a Custom SIP Trunk. To do it, you will need your Sub Account username and the IP address of your preferred VoIP.ms Point of Presence.

Adding the SIP trunk

To add a new SIP trunk in Vapi, follow these steps:

1. Log into your Vapi's dashboard: Vapi - Dashboard

2. Open the sidebar, and click on your username.

3. Click on Settings.

4. Click on Integrations.

5. On the list of integrations search for SIP Trunk.

6. Click on + Configure New SIP Trunk.

Fill the SIP configuration with these values:

1. Name: Any name of your choice (E.g. VoIPms trunk)

2. IP address/domain: Your Preferred VoIP.ms POP Server IP address (E.g. For example, for losangeles4.voip.ms use 208.100.60.38).

3. Port: 5060.

4. Netmask: 24.

5. Outbound Protocol: UDP or TCP.

6. Allow inbound calls: Checked.

7. Allow outbound calls: Checked (if needed).

8. Username: Your VoIP.ms Sub Account username (E.g. 100000_Vapi).

9. Password: Leave empty.

10.Use SIP Registration: Unchecked.

11. Click on + Save SIP Trunk.

Adding a Phone Number

Once you have configured the SIP Trunk, you can start adding your VoIP.ms DID numbers to Vapi.

Follow these steps to add a DID number:

1. On the sidebar click on Phone Numbers.

2. Click on Create Phone Number.

Add the number using this information:

1. From the options of the top, select BYO SIP Trunk Number'.

2. Phone Number: Your DID number in E.164 format (E.g. +1205XXXXXX).

3. SIP Trunk Credential: The trunk you configured for VoIP.ms.

4. Label: Any name of your choice.

5. Click on Import SIP Phone Number.

Gathering the info to configure the DID on VoIP.ms

Once the number is added to Vapi you will need to get an Universally Unique Identifier (UUID) that Vapi generated for your phone number.

Follow these steps to get the UUID.

1. On the sidebar click on Phone Numbers

2. Click on the Phone Number that was added to open its configuration.

3. Locate the UUID on the top right corner and click on the Copy icon.

 Paste this somewhere because you'll need it.

4. Assistant: Make sure to assign an AI assistant to your DID.

VoIP.ms DID configuration

To make VoIP.ms successfully route the calls to the trunk in Vapi you need to add the UUID to the Sub Account's domain used for IP Authentication and then route the DID to the Sub Account.

Adding the UUID to the Sub Account

Next you need to update the FQDN of the Sub Account by adding the UUID.

Follow these steps to do it.

1. Log into your VoIP.ms Customer Portal.

2. Go to Sub Accounts >> Manage Sub Accounts.

3. Click on Edit for the Sub Account you created and configured for Vapi.

4. On the field IP Address or Fully Qualified Domain Name paste the UUID at the beginning of the domain sip.vapi.ai. It will look something like a81bc81b-dead-4e5d-abff-90865d1e13b1.sip.vapi.ai

5. Click on Update Account.

Route your DID to the Sub Account

Once the Sub Account is ready, all you need to do is route your DID number to this so the calls connect to your Vapi's trunk.

1. Go to DID Numbers >> Manage DIDs.

2. Click on Edit for the DID number you added to Vapi.

3. Main Routing: Select SIP/IAX and from the list the Sub Account you added for Vapi.

4. DID Point of Presence: Make sure is the same server you used in the Vapi's SIP Trunk configuration.

5. Dialing Mode for Inbound Calls: E164

6. Apply changes when done.

That's it! Now the calls to your DID will be redirected to Vapi and answered by your Vapi's AI Assistant.

Outbound calls

Coming soon!

Useful resources

Vapi's documentation: SIP Trunking