Keep the backend you built.
Your existing agent receives a transcript and returns text over HTTP. Keep tool use and business logic in your application while AgentPhone manages speech.
See how it worksAgentPhone vs Retell
Connect your agent with a simpler Retell alternative.
Connect your agent to live calls with an HTTP webhook. Keep its memory, tools, and business logic in your application, and use the same event format for incoming messages.
Start buildingFree migration from Retell.
Your AI agent
AgentPhoneVoice
SMS / MMS
iMessage
WhatsAppBeta
RCSBeta
Keep building your agent.
We’ll handle the phone.
Reuse your response logic.
Voice and incoming messages share an event format. Handle the request in your backend and choose how your agent should respond to the conversation.
See how it worksGive the agent phone tools.
Use MCP to place calls, send messages, read threads, and get transcripts. Your agent can take phone actions as part of a larger task.
See how it worksGive your agent a number and let it work.
AgentPhone’s API signup returns an account, key, starter agent, and number after email verification. Your agent can then use MCP or the API to make calls, send messages, and retrieve conversations. You keep control of its reasoning and integrations.
- 1Your agent starts signup
The API sends a code to your email.
- 2You verify your email
It gets the account, key, agent, and number.
- 3Give it work to do
Connect its tools through MCP or the API.
Agent signup requires email verification. US outbound SMS requires carrier registration; iMessage requires access approval. Calling is subject to account verification and funding requirements.
What changes when
you use AgentPhone.
A focused comparison for teams bringing their own agent backend, with messaging alongside voice.
| What matters | AgentPhone | Retell |
|---|---|---|
| Existing-agent integration | HTTP transcript-and-text responseAny HTTP endpoint can answer a call turn. | Per-call WebSocket for a custom LLM ↗ |
| Your agent’s logic | Keep it in your application via webhookReasoning and tool calls stay in the code you already run. | Configure a prompt, flow, or custom-LLM integration ↗ |
| Voice and text setup | One agent.message event format for your backendOne event shape for voice and messages, handled in one place. | Separate chat and voice agent IDs in the widget setup ↗ |
| SMS for your agent | Provision an SMS-capable number and register itThe number your agent calls from can text too, once registered. | Enable SMS on a managed number or use custom telephony ↗ |
| Number setup | API signup includes a starter agent and numberA number comes with the account, so the first call needs no extra step. | Purchase a number, then configure inbound/outbound agents ↗ |
| Tools in your workflow | MCP for calls, texts, numbers, and conversationsTools let the agent place calls, send texts, and read threads directly. | MCP for managing Retell agents from coding tools ↗ |
Selected workflows from each platform’s documentation, checked 2026-09-22. Follow the source links for setup details and requirements.
A request, a reply, a conversation.
Retell’s custom-LLM integration uses a WebSocket for each call. AgentPhone’s webhook mode gives your backend a transcript and accepts its text response. That keeps the phone integration close to the request-and-response code you already write. Hosted voice is available too.
Let one agent call and message.
Keep a phone identity for your agent across voice and messaging. Add SMS, MMS, iMessage, WhatsApp, and RCS through AgentPhone. WhatsApp and RCS are in beta; iMessage requires access approval. Message threads and custom metadata help your agent pick up the next task with context.
We’ll help you make the move. For free.
Bring your Retell setup. We’ll help you connect your agent, plan the migration, and get started on AgentPhone. Volume pricing and price matching are available as you scale.
AgentPhone SMS includes carrier fees and taxes.
Your agent has work to do.
Give it a number.
Start building Bring your agent. We’ll help with the move.