Deploy your agent

One agent, bound by its agent_id, answers wherever you point it. Pick where.

From a browser

A web app, widget, or in-product voice. Your server mints a short-lived token so no API key reaches the page.

Over the phone

An inbound number people call. Twilio hands the call straight to AssemblyAI over SIP.

	Browser	Phone
Best for	Web apps, widgets, demos	Support lines, reception, order taking
You provide	A server endpoint that mints tokens	A Twilio account and a number you own
You run	Your web app	Nothing
Auth	Short-lived token, per session	API key, server-side at setup
Audio	The browser captures and plays it	Twilio and AssemblyAI handle it end to end
Echo	Handled by the browser, no headphones needed	Handled by the carrier
Setup	Minutes	About 10 minutes, mostly Twilio config

Want both? Publish the agent once and point both at the same agent_id. The Quickstart does exactly that in five commands.

Whichever you pick

Both open the same WebSocket, wss://agents.assemblyai.com/v1/ws, and bind the same way. Send one session.update with the agent_id and nothing else, and the stored prompt, voice, and tools load server-side:

{
  "type": "session.update",
  "session": { "agent_id": "7ad24396-b822-4dca-871a-be9cc4781cf9" }
}

Wait for session.ready before streaming audio, and finish with session.end. Skipping session.end leaves the session in a 30-second grace window that you pay for. See Ending the session cleanly.

agent_id is mutually exclusive with inline session fields. Binding to a stored agent and also sending system_prompt, greeting, tools, input, or output is rejected. To configure per session instead, send those inline and omit agent_id. See Inline configuration.

Neither of these

On another telephony provider, or embedding in something we don’t have a guide for? You connect the same way with your API key in the Authorization header, and move the audio yourself. Stream audio has the encodings and the send, play, and barge-in handling.

A raw API key is fine for servers and trusted backends. Never ship it in browser or mobile client code. Use the browser token flow for anything client-side.