Flow Messaging: WhatsApp, Telegram and iMessage API for AI agents

import { FlowMessaging, contentText } from "@flow-engineer/messaging";

const flow = new FlowMessaging(); // reads FLOW_MESSAGING_KEY

for await (const event of flow.events.stream({ types: ["message.received"] })) {
  const said = contentText(event.data.message.content);
  await event.conversation.reply(`You said: ${said}`);
}

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How it works

1. Flow hosts the senders: a Telegram bot or an iMessage line (and WhatsApp numbers once WhatsApp is available). Start on the shared Telegram sandbox bot; go live with your own Telegram bot, or an iMessage line the Flow team connects to your app.
2. A person messages your sender. Flow stores the message and delivers it to you as an event: by signed webhook, by a live WebSocket stream, or by polling the event log.
3. Your agent replies into the conversation with typed content (text, media, voice notes, buttons, reactions). Streamed LLM answers become natural chat bubbles.
4. Every send passes one send gate that applies each channel’s rules (who may be messaged, new-contact limits, pacing), so your sender stays healthy.
5. Delivery updates (message.sent, delivered, read, failed) come back as events in the same ordered log.

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Why it is built for AI agents

• Replies that read like a person typed them. Pass an OpenAI, Anthropic, Vercel AI SDK, LangChain or Mastra stream to reply() and the SDK keeps the typing indicator on and sends paragraph-sized bubbles as they are ready. See Streaming replies.
• Reply in the webhook response. Answer a message.received delivery with {"reply": ...} and save a round trip. See Events and webhooks.
• Nothing converted silently. If a channel cannot show something (buttons on iMessage), the API says so, or sends the fallback you chose and reports what was shown. See Content types.
• Errors an agent can act on. Every error has a closed type, a one-line hint and a doc_url. See Errors.
• Works from coding agents. A Claude Code skill and an AGENTS.md snippet let Claude Code, Codex and Cursor integrate Flow for you, and an optional MCP server you can add to them helps test it while you build. See For AI coding agents.
• Language-neutral. Everything is plain HTTP and JSON with an OpenAPI 3.1 spec, so any language works today.

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Packages

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Channels

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Next steps