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Voice AI
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PUC
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AI Sidecar is real-time agent assist that never joins the call. Starting September 15, 2026, you can attach it to any live call on SignalWire, where it listens as the conversation happens, matches what you told it to listen for, and delivers it wherever it needs to go. That might be an answer on an agent's screen, an alert in a supervisor's queue, or a flag in your compliance record. The customer hears only the person they called.
What is AI Sidecar?
If you've tried to add real-time AI awareness to a live conversation, you already know the workaround: stream the audio off the call, transcribe it, and ship it to a language model. It works, technically, but it's slow. Coaching prompts and alerts often arrive several seconds after the moment that mattered, a few words at a time. Some teams have even resorted to dropping an AI assistant into a conference bridge on mute, just to get it listening.
AI Sidecar runs as an agent attached directly to the call inside SignalWire's media infrastructure. It doesn't have to wait for audio to leave the platform, get transcribed, and get batched up. It processes what it hears as the conversation unfolds and posts what it notices straight to your webhook, no separate transcription pipeline required.
What it isn't
AI Sidecar doesn't speak into the call, and it doesn't come with a built-in agent-facing screen or widget. It's a listener, not a participant. Everything it produces is delivered out of band, to your server, for you to act on however you'd like.
Use cases
AI Sidecar is the primitive underneath agent assist, supervisor alerting, and compliance monitoring: a primitive in Call Fabric, a building block, not a finished application. What you build with it is up to you.
Live coaching: Real-time sales coaching software
Feed real-time signals to a rep or agent while they're still on the call. Flag when a competitor is mentioned, surface a relevant answer, or nudge toward a next step, all delivered to whatever interface you already use for coaching.
Supervisor alerting: Call center coaching in real time
Let a sidecar watch for the moments that matter: an escalation, a specific keyword, a tone shift. Then notify a supervisor the instant it happens, instead of relying on someone catching it live or reviewing it after the fact.
Compliance monitoring and call center quality monitoring software
Have the agent listen for disclosures, required language, or prohibited topics as the call happens, and route findings to your compliance tooling in real time rather than after a recording is reviewed.
Multi-party observation
AI Sidecar can listen to one leg of a call or both. You tell it which leg is the customer and which legs matter for context, which is useful for calls with more than two participants where you need to know who said what. For a multi-party call, you'd typically run one sidecar per leg and mix the output on your side, producing a running log of the conversation rather than a single end-of-call summary.
These are just starting points. Because delivery is a webhook, AI Sidecar fits into whatever workflow, dashboard, or automation you already have.
How AI Sidecar works, at a high level
Whether you're building agent assist for live coaching or a compliance pipeline, the setup is the same. You attach an AI Sidecar agent to a call (one leg or both) through the SignalWire Server SDK, the same SDK you’re likely already using to build call handling. You tell it which leg represents the customer and which legs should count as context versus which are actionable. As the call happens, it sends what it observes to a webhook endpoint on your server. From there, it's yours: log it, route it, display it, act on it.
All you need is a call on SignalWire and a server ready to receive the webhook.
Pricing
AI Sidecar is available now at no charge while we finalize pricing. It will be billed per minute while a sidecar session is running, regardless of how many legs it monitors. We will give at least 30 days notice before billing begins.
Get started with AI Sidecar
AI Sidecar is available today with no beta and no feature flag. If you have a SignalWire account, you can start building with it now. Documentation is available to help you get a webhook receiving live call signal for the first time.
This is just the beginning for AI Sidecar. We're exploring voice whisper, which could let a sidecar speak directly to an agent mid-call, along with support for asynchronous tool calls so a sidecar can pre-fetch what an agent is about to need while a conversation is still going. Today AI Sidecar listens, understands, and delivers what it heard, fast enough to matter. Next, it starts acting.
Start building AI into your calls today with a free SignalWire account, and join our developer community on Discord.
What is agent assist?
Agent assist is technology that gives a rep or agent real-time support while they're still on a call by surfacing relevant information, flagging important moments, or prompting a next step as the conversation happens, rather than after it ends. Traditional agent assist tools typically work by streaming call audio to a transcription and language model pipeline, which introduces a delay between when something is said and when the assist signal arrives.
Does AI Sidecar speak on the call?
No. SignalWire’s AI Sidecar only listens. It doesn't speak into the call or interact with the people on it. Everything it produces is delivered out of band, to your server, for you to route or display however you choose.
Does AI Sidecar include a dashboard or user interface?
Not in this release. SignalWire’s AI Sidecar is a developer primitive: you build the interface, alert, or workflow on your end using the data it sends to your webhook. There's no built-in agent-facing widget.
Can AI Sidecar listen to only one leg of a call?
Yes. You can attach it to one leg or both, and tell it which leg is the customer versus which legs count as context. Listening to only one leg means you'll only get visibility into that side of the conversation, so choose legs based on what you need to observe.
How much does AI Sidecar cost?
AI Sidecar is available at no charge during its introductory period. SignalWire will provide a notice period before any billing begins, so there's no surprise switch-over.
What tools do I need to use AI Sidecar?
A call on SignalWire and a server ready to receive a webhook. You attach and control AI Sidecar through the SignalWire Server SDK, so if you're already building call handling on SignalWire, there's no separate integration to stand up.
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