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Voice Calling (telephony)

The Voice Calling tab on the Deployment screen connects a voice agent to a phone number via a third-party telephony provider. Inbound and outbound calling are configured here.

Picking a provider​

Supported providers today:

  • WhatsApp
  • Twilio

Connection credentials (number and token) are persisted under Connections → Service Provider, but you can add and edit them directly from the Voice Calling tab as well.

Inbound calling​

To receive calls into a voice agent:

  1. Add provider credentials — phone number and provider token. The credentials persist in Connections → Service Provider.
  2. Assign the phone number to the voice agent. A phone number that's already assigned to one agent cannot be assigned to another until it's removed from the first.
  3. Configure call settings — these depend on the provider's capabilities (call recording opt-in, greeting messages, etc.).

The connection status for each provider is shown in the Voice Calling tab so you can see at a glance whether the integration is live.

Outbound calling​

Voice agents expose an outbound calling API that lets you trigger a call from your application code or another workflow.

The payload to the outbound API:

  • Target user phone number — required. The number the agent dials.
  • Target user name — optional. Displayed in the run history and available to the agent's prompt.
  • Environment variables — optional. Per-call values that the agent's environment variable bindings can reference.

The API returns a conversation ID which you can use to fetch the recording and transcript later.

Outbound calling from a workflow​

In addition to the REST API, you can trigger an outbound voice agent call from a Tool using the Voice Agent node. See Voice Agent as a workflow node for the node configuration — it's the same parameters wrapped in a no-code node.

What gets billed​

Voice Calling adds call connection charges to a voice agent's billing — these come from your telephony provider directly, not SimplAI. The per-second voice metering on the SimplAI side is unchanged. See Pricing.

Audit logging​

Telephony connections emit audit events:

  • Create / edit / delete a telephony integration (the integration itself is the resource).
  • Add / remove a telephony integration from a voice agent.

These appear in the workspace audit log alongside the standard voice agent events.