DIDLogic SIP integration

Connect your DIDLogic SIP trunk to Vapi so your assistants can receive and place phone calls. This guide covers outbound calling through DIDLogic, inbound routing to Vapi, and optional SIP REFER transfers.

For SIP trunking concepts and network requirements, see the SIP trunking guide.

Use the Vapi dashboard, SIP hostname, and API resources for the region where your organization is hosted. This guide provides both US and EU SIP routing formats.

Prerequisites

Before you begin, make sure you have:

An active DIDLogic account with a positive balance
At least one purchased phone number in the DIDLogic customer portal
An active DIDLogic SIP account
A Vapi account and assistant

Configure outbound calling

Create a DIDLogic SIP trunk credential

In the Vapi dashboard, select your organization name, then go to Settings → Integrations → SIP Trunk and click Configure New SIP Trunk.

Configure the credential with your DIDLogic SIP account details:

Name: A descriptive name, such as DIDLogic
IP Address / Domain: A DIDLogic regional SIP gateway, such as sip.nl.didlogic.net
Username: Your five-digit DIDLogic SIP username
Password: Your DIDLogic SIP password

Save the credential and note its credential ID. You will use this ID when configuring inbound routing.

Import your DIDLogic phone number for outbound calling

To place outbound calls with the SIP trunk credential, the DIDLogic phone number must be available in Vapi. Go to Phone Numbers. If your DIDLogic number is not already listed, click Create Phone Number and select BYO SIP Trunk Number. If the number is already listed, open it to update its configuration.

Enter or confirm your DIDLogic phone number and select the DIDLogic credential in the SIP Trunk Credential dropdown. If the number will also receive inbound calls, assign the assistant that should answer them. Save the phone number.

Configure inbound call routing

Open the DIDLogic destination settings

Sign in to the DIDLogic customer portal, go to Purchased, find the phone number you imported into Vapi, and click Edit in the Destination section.

Route the number to Vapi

Set Destination Type to SIP URI, then enter the URI for your Vapi region:

# US organization
YOUR_PHONE_NUMBER@YOUR_CREDENTIAL_ID.sip.vapi.ai
# EU organization
YOUR_PHONE_NUMBER@YOUR_CREDENTIAL_ID.sip.eu.vapi.ai

Replace YOUR_PHONE_NUMBER with the DIDLogic number you imported and YOUR_CREDENTIAL_ID with the Vapi SIP trunk credential ID. Do not use a Vapi private API key in the SIP URI.

Click Add to save the destination.

Test the integration

Test outbound calling

In Vapi, select an assistant and the imported DIDLogic phone number.
Place a test call to a phone you can answer.
Verify that the call connects and displays the expected caller ID.

Test inbound calling

Dial your DIDLogic phone number from an external phone.
Verify that Vapi receives the call and the assistant assigned to the number answers.

Configure SIP REFER transfers

To transfer an active call through DIDLogic, ask your DIDLogic account manager to enable SIP REFER for your account.

DIDLogic may restrict SIP REFER transfers to other DIDLogic numbers. Confirm the supported destinations and required routing with your DIDLogic account manager.

Create a transfer tool

In Vapi, go to Tools → Create Tool → Transfer Call. Add a SIP destination and enter a URI in the following format:

sip:+E164_NUMBER@YOUR_DIDLOGIC_GATEWAY

For example, sip:+31203691111@sip.nl.didlogic.net.

Configure and assign the tool

Add a customer message and destination description, keep Blind Transfer selected so the transfer uses SIP REFER, and save the tool. Add the transfer tool to your assistant and publish the assistant.