Receive calls on a number

An inbound connection routes calls that arrive on a number you own to one agent. For how connections work and where they live, see Connect a phone number.

Prerequisites

Before you begin:

A number from a carrier, in E.164 format (+15551234567).
Admin access to your SLNG organization. Creating a connection is a dashboard task, and the Telephony section is admin-only.
An agent to answer the calls. Keep its ID for the API path. If you do not have one, see Create an agent.
An SLNG API key for the API path. See Create your API key.

Create the connection

Open the Telephony section

In the dashboard sidebar, open Telephony, switch to the Inbound tab, and click Add connection.

The Inbound tab of the Telephony section with the Add connection button — The Inbound tab of the Telephony section. Add connection starts the inbound setup.

Choose a setup mode

Choose Twilio to generate a webhook URL. Choose Manual to generate SIP forwarding targets and optionally restrict source addresses.

Name the connection and add your numbers

Give the connection a name you will recognize in the agent picker, such as wayne-enterprises-support. Add the phone numbers that should reach the agent, one per line or comma-separated, each in E.164 format.In Manual mode you can also set Allowed addresses to restrict which source addresses may send calls to this connection. Leave it empty to accept calls from any address your carrier uses.

Create the connection and wait for it to become active

Click Create connection. The connection starts as pending while provisioning finishes, then becomes active. If it ends in error, open the connection to see the reason. You cannot attach it until it is active.

Route calls from your carrier

Your carrier must route incoming calls to the connection. A Twilio number sends an HTTP request to the generated webhook URL. Another carrier forwards calls to the generated SIP target.

Twilio
Any SIP carrier

Open the connection’s View setup and copy the webhook URL. In the Twilio console, open the number’s Voice configuration. Under A call comes in, choose Webhook, paste the URL, and select HTTP POST.

The inbound connection detail in Twilio mode, showing the webhook URL and a copy button — A Twilio inbound connection shows one webhook URL to paste into the number's voice settings.

Twilio Edit voice configuration screen with the voice webhook set to the SLNG inbound URL and HTTP POST — In the Twilio console, set the number's voice webhook to the SLNG URL, with HTTP POST.

The URL carries a token that identifies the connection, so treat it like a credential and do not publish it. If the connection shows no webhook URL yet, it has not finished provisioning.

Attach the connection to an agent

An inbound connection belongs to one agent at a time, because a call arriving on the number has to reach a single destination.

Dashboard
API

Open the project, go to its Telephony section, and pick the connection under Inbound calls. Connections you cannot pick are disabled and marked (Unavailable) with the reason.

The project Telephony section with the inbound connection dropdown open — The project's Telephony section, with the inbound connection picker open.

List the connections available to the agent.

Request

curl https://api.agents.slng.ai/v1/agents/$AGENT_ID/sip-trunk-options \
  -H "Authorization: Bearer $SLNG_API_KEY"

Response

{
  "inbound": [
    {
      "id": "3f9c1b4e-5a27-4f8d-9c11-7b2e6d4a8c05",
      "name": "wayne-enterprises-support",
      "livekit_trunk_id": "ST_b6TUc5Q7bZMD",
      "numbers": ["+15551234567"],
      "status": "active",
      "selectable": true,
      "is_current": false,
      "unavailable_reason": null
    }
  ],
  "outbound": []
}

Copy the id of a connection where selectable is true, then set sip_inbound_trunk_id on the agent.

Request

curl -X PATCH https://api.agents.slng.ai/v1/agents/$AGENT_ID \
  -H "Authorization: Bearer $SLNG_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{ "sip_inbound_trunk_id": "3f9c1b4e-5a27-4f8d-9c11-7b2e6d4a8c05" }'

A successful response returns the updated agent with sip_inbound_trunk_id set to the connection ID. Sending null detaches the connection and leaves it free for another agent.

When a connection cannot be attached

The dashboard disables unavailable connections. The API returns the reason in unavailable_reason. See When a connection cannot be attached.

Verify inbound calls

Call one of the connection’s numbers from another phone. The agent should answer and use inbound_greeting when you have set one. If the call does not reach the agent, confirm that the connection is active, attached to the agent, and using the carrier settings shown under View setup.

Greet inbound callers differently

With a connection attached, the agent can use inbound_greeting instead of its default greeting, so a caller who dials in hears something different from someone the agent called. Directional greetings need at least one connection attached, inbound or outbound, and the agent fails to save without one. See Update an agent for the update mechanic.

Change or replace the credentials

Manual connections authenticate with a SIP username and password, shown under View setup. To change them, open Edit and update both values together. Configure your carrier to use the same pair. Coordinate the change because calls can fail while the two sides use different credentials. Twilio inbound connections do not use a SIP username and password. The webhook URL contains the connection token, and the dashboard cannot rotate that token in place. If the URL is exposed, contact SLNG support to replace the connection. Replacing it may briefly interrupt inbound calls.

Next steps

Place calls from an agent if the agent also needs to dial out or transfer callers to a person.
Debug a call to review each call’s transcript and events.

Get started

Regions

Execution layer

Agent Builder

Models

Integrate

Prerequisites

Create the connection

Route calls from your carrier

Attach the connection to an agent

When a connection cannot be attached

Verify inbound calls

Greet inbound callers differently

Change or replace the credentials

Next steps

​Prerequisites

​Create the connection

​Route calls from your carrier

​Attach the connection to an agent

​When a connection cannot be attached

​Verify inbound calls

​Greet inbound callers differently

​Change or replace the credentials

​Next steps

Prerequisites

Create the connection

Route calls from your carrier

Attach the connection to an agent

When a connection cannot be attached

Verify inbound calls

Greet inbound callers differently

Change or replace the credentials

Next steps