AI voice agents for contact centers

A ThunderPhone agent can answer calls inside the contact center you already run. Your platform sends the call to the agent over SIP, along with what it already knows about the caller. The agent handles the conversation. When the caller needs a person, the agent hands the call back with a summary, an intent label and an id your flow can look up, so the person who picks up doesn't start from zero.

Your platform keeps the phone numbers, queues, human agents and reporting. The AI agent is one step in your flow, and your flow decides what happens before and after it.

Setup guides: every platform below has a step-by-step guide in the docs, with the exact API calls, headers and test steps. Start at Contact centers in the ThunderPhone docs.

Supported platforms

Platform	How the call reaches the agent	How it comes back
Five9 (not yet accredited)	AI Agent Connect, set up by Five9, dials a number	The agent hangs up with routing headers the IVR script reads
Genesys Cloud	BYOC Cloud trunk to the agent's SIP address	`REFER` accepted by Take Back and Transfer, hand-off id in UUI
Amazon Connect	External voice transfer connector	The flow resumes and a Lambda looks up the hand-off
Microsoft Dynamics 365 Contact Center	Transfer to a number, through your SBC	Your SBC brings the caller back; an HTTP Request node looks up the hand-off
NICE CXone	Studio Placecall with custom headers	The agent hangs up; a REST API action looks up the hand-off
Talkdesk	Connect to Autopilot Voice	`REFER` to Talkdesk's escalation address, hand-off id in UUI
Twilio and Twilio Flex	TwiML `<Dial><Sip>`	`REFER` to your `referUrl` handler, which can enqueue to Flex
Zoom Contact Center	Bot widget, on a trunk Zoom builds	`REFER` to Zoom's human-agent address

How it works on every platform

A SIP endpoint for the agent. Platforms that can answer a password challenge use the endpoint's username and password. Platforms that identify themselves only by source address get an IP allowlist. Platforms that dial a phone number rather than a SIP address reach the endpoint through a dial-in number.
Context in. Every X- header and User-to-User value the platform sends becomes a call variable the prompt can use, such as {{sip_x_customer_tier}}. The platform's own call id is stored on the call as its external_call_id.
A way back. One transfer entry hands the call back. Either the agent sends a SIP REFER to an address on your platform, or it returns the call: it says goodbye, hangs up, and your flow carries on.
The hand-off. At the transfer the agent writes a summary of what the caller needs (up to 300 characters), a short intent label such as billing_dispute, and a hand-off id. Headers carry them where the platform can read them. Any flow can also fetch them from the hand-off lookup API, by your platform's call id or by the hand-off id. Once the call has ended, the lookup also returns the call summary and extracted data.

The agent on these calls is the same agent you'd put on a ThunderPhone number: its prompt, voice, 47 languages, knowledge and tools such as calendars, CRMs and MCP servers. You test it with simulated callers and regression suites before it takes traffic, and watch its calls in call history afterwards.

Before you start

These are SIP integrations, not marketplace apps. ThunderPhone isn't listed on any contact-center marketplace yet, and it isn't a Five9-accredited AI Agent Connect provider. You set the integration up from the docs guide, with your platform's admin or vendor where noted.
Some platforms need their vendor first. Five9 sets up AI Agent Connect. NICE turns on custom headers for the trunk group. Zoom's ISV team builds the trunk. Amazon has to approve a quota increase before the connector appears.
The hand-back is a cold transfer plus data. The person who takes the call reads the hand-off rather than hearing the agent introduce the caller. A warm transfer to a SIP address runs as a cold transfer.
Header values come from whoever sends the call. Use them as context in the prompt, not to decide who the caller is or what they may do.
Two bills per minute. Your platform bills its side of the call. ThunderPhone bills the agent's minutes.

Frequently asked questions

Which contact-center platforms can send calls to a ThunderPhone AI agent?

Amazon Connect, Five9, Genesys Cloud, Microsoft Dynamics 365 Contact Center, NICE CXone, Talkdesk, Twilio (including Flex) and Zoom Contact Center each have a setup guide in the ThunderPhone docs. Any other platform or PBX that can send a SIP call can reach an agent's SIP address the same way, without a platform-specific guide.

Is this a native app on the contact-center marketplaces?

No. Each integration uses features the platform already has, such as a SIP trunk, a transfer block or a voicebot connector, plus ThunderPhone's SIP endpoints and hand-off lookup API. ThunderPhone isn't listed on any contact-center marketplace today.

What does the human agent get when the AI hands the call back?

The AI agent writes a summary of what the caller needs and what it already did, plus a short intent label, at the moment of the transfer. Depending on the platform, these arrive in SIP headers or UUI, or your flow fetches them from the hand-off lookup API by its own call id. Your flow can route on the intent and show the summary to the person who takes the call.

What does it cost?

Calls that come from your contact center are billed at the agent's normal per-minute rate: 2¢ a minute on Spark, 5¢ on Bolt and 9¢ on Storm, with published add-ons such as premium voices on top. There is no phone-number charge, because no ThunderPhone number carries the call. Your contact-center platform bills its own side. See ThunderPhone pricing.

Do I have to change my phone numbers or IVR?

No. Callers keep dialing the numbers they use today, and your existing flow decides when to send a call to the agent. You add one step that sends the call over SIP, and one that picks it up again when the agent hands it back.

Is it HIPAA and GDPR compliant?

ThunderPhone is HIPAA compliant, BAA available, and GDPR compliant, DPA available. Your contact-center platform has its own compliance terms for its side of the call.