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Chat agents hold text conversations with your users. They use the same prompt types, functions, and knowledge bases as voice agents, so you can offer the experience you built for calls over text as well — on your website, over SMS, or inside your own app.
Retell has no built-in integrations with third-party chat platforms such as WhatsApp or Messenger. Beyond the website widget and SMS, you connect your own channel through the chat API.

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When to use a chat agent

Use a chat agent when your users type instead of talk:
  • Website support — answer product, billing, or order questions in a chat widget on your site.
  • SMS conversations — run two-way text threads on a Twilio number, such as appointment reminders with reschedule handling.
  • In-app assistant — power a chat UI you build into your own web or mobile app.
For example, an e-commerce store embeds a chat agent in its help center to handle order-status questions: the agent looks up the order with a custom function and replies with the tracking link, so support staff only see the conversations the agent escalates.

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Create a chat agent

1

Start a new agent

In the dashboard, open Agents, click Create an Agent, and select Chat Agent.
2

Pick an agent type

Choose Single prompt for simple free-form conversations or Conversational flow for production-ready, deterministic flows. Multi-Prompt (Legacy) is available under Other options. Custom LLM is voice-only, so it can’t power a chat agent.
3

Configure the agent

Write the prompt, attach functions and a knowledge base, and adjust the chat settings described below.
Retell dashboard Agents page with the Create an Agent dropdown open, showing Voice Agent and Chat Agent options with Chat Agent highlighted

The Create an Agent menu on the Agents page, with the Chat Agent option highlighted.

To create chat agents programmatically, call Create Chat Agent with a Retell LLM or conversation flow response engine.

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Convert an existing voice agent

Converting creates a new chat agent based on your voice agent’s setup. The original voice agent is not modified and keeps working as before.
1

Open the voice agent

In the agent builder, click the More options menu in the top-right corner and select Convert to Chat Agent.
2

Confirm the conversion

A dialog confirms that a new chat agent will be created and your original agent stays unchanged. Click Convert.
3

Review the new chat agent

Retell opens the new chat agent. Voice-only features are removed during conversion, so review the prompt and flow and adjust anything that referenced them.
Conversion removes what doesn’t apply to text:
  • Nodes and functions: call transfer (including bridge and cancel transfer), press digit (IVR navigation), and mid-call SMS are deleted, and any dangling flow connections are cleaned up.
  • Settings: voice, speech, transcription, and call settings (voicemail detection, DTMF input, and similar) don’t exist on chat agents.
Three-step sequence in the agent builder: the More options button in the top-right corner is highlighted, then the open menu with Convert to Chat Agent highlighted, then the confirmation dialog explaining a new chat agent will be created while the original stays unchanged, with the Convert button highlighted

Converting a voice agent: open More options, select Convert to Chat Agent, and confirm in the dialog.

Conversion works in both directions: a chat agent’s More options menu offers Convert to Voice Agent.

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Chat settings

Chat agents share most configuration with voice agents — prompt, functions, knowledge base, webhooks, security, and post-chat analysis — and add a Chat Settings section:
  • Auto-close inactive chats — end the chat automatically when the user stops responding. Set the timeout anywhere from 2 minutes to 72 hours (end_chat_after_silence_ms; the API default is 1 hour).
  • Auto-close message — an optional message sent when a chat is closed automatically (auto_close_message).
For chat events, webhooks fire chat_started, chat_ended, and chat_analyzed by default; add transcript_updated through the agent’s webhook_events if you need per-message updates.

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Deploy your chat agent

Chat agents are headless — Retell does not host a chat UI for end users, so you choose how to surface the agent:
  • Website widget — embed a single <script> tag on your site for text (and optional voice) chat with no backend required. See Retell Website Widget.
  • SMS — connect the agent to a Twilio phone number so users can text it directly. See Enable SMS.
  • Custom integration — build your own UI on the chat API: Create chat starts a session, Create chat completion exchanges messages, and the session stays open until you call End chat or the inactivity timeout closes it.
Once live, set up alert rules on chat volume, success rate, negative sentiment, or cost to hear about problems without watching the dashboard.

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FAQ

No. Chat agents support Retell LLM (single and multi prompt) and conversation flow response engines. Custom LLM agents are voice-only.
No. Conversion creates a separate chat agent; the original voice agent is untouched and any phone numbers attached to it keep working.
Three ways: the agent ends it (an end-chat node or function), you end it with the End chat API, or the user goes silent past the inactivity timeout and Retell closes it automatically.
Chat is billed per agent message, with add-ons (such as guardrails) also charged per message. See pricing for current rates.