The fastest way to get Fin Voice live and integrated with your existing phone system is by using PSTN (Public Switched Telephone Network) call forwarding. This method works universally with any telephony provider and is the recommended entry point for pilots and early deployments.
What is Fin Voice?
Fin Voice is Intercom’s AI Agent for phone support. It answers calls instantly, resolves questions using your help content, and can seamlessly hand off the call to a human teammate with full context when needed.
Fin Voice is designed to integrate with any existing telephony provider, allowing you to keep your current phone system while adding powerful AI-powered support.
How the integration works
This setup uses standard PSTN forwarding to route incoming calls from your telephony provider to a dedicated Intercom number for Fin Voice. It does not require SIP (Session Initiation Protocol), which is why it is universally supported.
You can migrate to a cheaper, more robust SIP-based deployment later if your provider supports it.
Why we recommend PSTN for trials
PSTN forwarding is the recommended entry point for pilots and early-stage deployments for two main reasons:
It is the fastest way to get customers live.
It is universally supported by every platform and requires minimal setup.
Setting up the Fin Voice call flow
Prerequisites
To set up this integration, you'll need the following:
Requirement | Description |
Intercom workspace | Fin Voice must be enabled and hosted in the US, EU, or AU region. |
Intercom admin access | Permissions are required to set up and manage Fin Voice. |
Knowledge base | Fin needs access to rich, up-to-date support content. |
Telephony admin access | Ability to edit call routing or forwarding rules in your external provider. |
External phone number | Active inbound numbers on your telephony provider. |
Optional: IVR workflow with HTTP request capability | Required only if you want to use the Fin Voice API to pass summaries, transcripts, and intent to your agents. Your provider must support making HTTP requests from an IVR or call routing workflows. |
1. Test Fin Voice
You can simulate calls in-browser using the Voice testing tab before involving any real customers.
Click Test.
Wait for Fin to greet you, and then begin speaking normally. Allow your browser access to your microphone if prompted.
Tip: This test allows you to hear Fin answer using your own support content, switch voices, and preview greetings and escalation rules exactly as callers would hear them.
2. Create a Fin Voice line
When you're ready to set up a live phone line, you'll purchase a number from Intercom that your provider will forward calls to.
Navigate to Fin AI Agent > Deploy > Phone > Set Fin Live.
Click New line.
Select External provider and hit Next.
Give the line a name (e.g., "Fin Voice").
Under 'Where will you forward calls from?', select From a phone number (PSTN), then choose Next.
Select Purchase to acquire a US local phone number provided through Intercom Phone.
Note: When calls are forwarded over PSTN, Intercom Phone usage charges apply. These charges include a monthly fee for the US local number, and inbound/outbound per-minute charges. These are separate from Fin Voice's per-resolution pricing.
3. Configure Fin’s behavior
You can customize how Fin operates before integrating with your telephony provider.
Open the line you just created in Fin AI Agent > Deploy > Phone > Set Fin Live.
Review and adjust these optional settings:
Office hours: Choose when Fin should answer calls (defaults to 24/7).
Voice, language, and greetings: Select Fin's voice, language, and customize the greeting.
Audiences: Restrict which support content Fin can use by targeting specific callers or phone numbers.
Guidance: Set rules for Fin's communication style and when it should escalate.
Category Detection: Enable AI-based topic classification for routing or reporting.
CSAT: Enable keypad ratings (1–5) for resolved calls.
Enable recordings and transcripts
To review customer interactions and see how Fin handled each call, enable recordings and transcripts.
Navigate to Settings > Channels > Phone.
Enable the toggles for recordings, transcripts, and call summary.
Note: This is a global setting for all Phone calls. It's not possible to only enable recordings or transcripts for some calls.
4. Forward calls to Fin Voice
In your telephony provider's routing or IVR editor, forward incoming calls to the Intercom number you purchased.
The flowchart showing the initial transfer from the IVR to Fin.
5. Configure Handovers Back to Your Provider
Set up a way for Fin to transfer the call back to your human team when it can't resolve a question.
Create a dedicated escalation number in your telephony provider. This number should route callers to your team's call queue.
In Intercom, go to Fin AI Agent > Deploy > Phone > Set Fin Live.
Under 'If Fin can’t resolve the conversation', select Forward the call and enter the escalation number you created in your provider.
Select the option to Close the conversation when the call is forwarded.
The flowchart showing the transfer back from Fin to the Call Queue.
Add context to handovers using the Fin Voice API
Use the Fin Voice API in your provider’s call flow to pass Fin’s summary, transcript, and intent to your teammates. These details are available within seconds of the call ending, giving teammates the context they need to assist customers smoothly.
1. Generate an API token
Open the Intercom Developer Hub and select New app.
Enter a name for your new app and make sure the workspace selected is the same one where you configured your Fin Voice agent.
Select Create app.
Copy the access token and store it somewhere secure. You will use this token as the Bearer token to authorize your Fin Voice API requests.
2. Register the call
Now that you have an access token, add the /register call to your provider’s routing or IVR flow before forwarding the call to Fin.
This creates a new Fin Voice session in Intercom and links the caller’s phone number and your provider’s call identifier to the conversation.
For complete documentation on parameters and response schemas, refer to the Register Fin Voice call developer documentation.
Endpoint: POST https://api.intercom.io/fin_voice/register
Parameters:
phone_number: Should be the caller’s number from your IVR or call context.call_id: Should be a unique call identifier provided by your telephony vendor.
curl -X POST https://api.intercom.io/fin_voice/register \
-H "Authorization: Bearer <YOUR_TOKEN>" \
-H "Content-Type: application/json" \
-d '{
"phone_number": "<caller-phone-number>",
"call_id": "<provider-call-id>"
}'
Important: The call must be registered before you call /collect. If you prefer to register after forwarding, it must happen within 2 minutes of Fin receiving the call.
The flowcharts showing the /register and /phone_number API calls.
3. Retrieve call data on handover
After Fin forwards the call back to your provider, you must retrieve the call summary, transcript, and intent using the caller’s phone number.
Note: PSTN escalation creates a new call leg, so the provider’s original call ID cannot be used to retrieve call details.
For complete documentation on parameters and response schemas, refer to the Collect Fin Voice call by phone number developer documentation.
Endpoint: GET https://api.intercom.io/fin_voice/phone_number/<caller-phone-number>
Parameters:
p
hone_number: The caller’s phone number in E.164 format (e.g., +353876747694).
curl -X GET "https://api.intercom.io/fin_voice/phone_number/<caller-phone-number>" \
-H "Authorization: Bearer <YOUR_TOKEN>"
Example Response:
{
"id": "12345",
"app_id": "app123",
"user_phone_number": "+353876747694",
"status": "escalated",
"intercom_call_id": "67890",
"external_call_id": "provider-call-id",
"intercom_conversation_id": "conv456",
"call_transcript": "",
"call_summary": "",
"intent": []
}
You can use these fields to populate your provider’s inbound call notification, giving teammates the summary and transcript from Fin before they pick up the escalated call.
Migrating to a SIP deployment
If you decide to add Fin Voice to your Intercom plan, our team can help you migrate to a SIP forwarding setup if your telephony provider supports it.
SIP delivers calls to Fin Voice over the internet rather than the phone network, which removes Intercom Phone per-minute charges for calls delivered over SIP.
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