WhatsApp AI agent API

Launch an AI agent on WhatsApp, without the webhook plumbing.

Connect your WhatsApp Business number to Flow and ship an agent that takes orders, books appointments and answers customers in seconds, with buttons, voice notes and read receipts.

Start building free Flow Framework on GitHub

Connect the number from your WhatsApp Business Account; Flow handles webhooks, retries and the 24-hour window.

DoorDashorders & delivery

reorder my usual from Thai Basil, extra spicy9:14 ✓✓

Thai Basil · 25 minPad thai, extra spicy

$18.40Card •• 4242

Place orderChange

Place order9:14 ✓✓

Ordered 🛵 Arriving 7:52 PM. I’ll text when the courier is close.9:14

Message

Illustration, not a Flow customer.

What you can build

Agents that do the task,
right in the chat.

Travel

A trip concierge that rebooks in one message

Check-in times, door codes and changes to the booking, answered from your own systems at 2am in the guest’s language.

Learning

Daily practice as a conversation

Quizzes, voice notes for pronunciation and a nudge before the streak breaks.

Fintech

Money questions answered with real numbers

Balances, card freezes and spending summaries for signed-in customers.

Retail

Shopping that ends in a checkout

Stock checks, sizes and reorders, with the receipt in the same thread.

Brand examples are illustrations of what could be built, not those companies' products.

Use cases

Build for the job your customers need done.

WhatsApp AI agent for travelCheck-in times, door codes and changes to the booking, answered from your own systems at 2am in the guest’s language.WhatsApp AI agent for learningQuizzes, voice notes for pronunciation and a nudge before the streak breaks.WhatsApp AI agent for fintechBalances, card freezes and spending summaries for signed-in customers.WhatsApp AI agent for retailStock checks, sizes and reorders, with the receipt in the same thread.

The usual way vs. Flow

The WhatsApp API takes weeks to set up.
With Flow it’s an afternoon.

Building it yourself~4 weeks

Meta Business account and verification 2–5 days
Meta app, phone number, webhook 1–2 days
Template approval 1–2 days
Agent loop, state, memory 1 week
Retries, dedupe, media, 24h window 1 week
Hosting, logs, tests 3–5 days

And then it only works on WhatsApp. iMessage, Telegram, ChatGPT and Claude are each a new build.

With Flow Frameworkan afternoon

Create the project1 min
Write your tools1–2 hrs
Test, connect your number, go live30 min

tools/book-table.ts

import { tool } from "@flow-engineer/flow";
import { z } from "zod";

export default tool({
  name: "book_table",
  description: "Book a table when the customer asks for one.",
  input: z.object({ time: z.string(), guests: z.number() }),
  run: async ({ time, guests }) => api.bookings.create({ time, guests }),
});

How Flow works

Write it once. Ship it to WhatsApp and everywhere else.

Tools, not plumbingYou write what the agent can do. Flow handles webhooks, retries, ordering and media.
Memory per customerEach customer’s conversation is kept between chats, so they can pick up where they left off.
Tested before it’s liveScenario tests with simulated users run before every release, and every turn is traced after.

Get started

How to build a WhatsApp AI agent with Flow.

Create a Flow project
Run npx @flow-engineer/flow new my-agent, or ask Claude Code or Codex to set it up. You get one folder: the agent’s instructions, its tools, its skills and its tests.
Write what it can do as tools
Each job is a TypeScript function with a typed input that calls your API: check an order, book a slot, find a deal. No protocol code.
Test it on simulated users
Run npx @flow-engineer/flow test. Simulated users try the scenarios that matter, including people who change their mind or ask for something your agent should refuse.
Connect your WhatsApp number
Connect a number from your WhatsApp Business Account in the dashboard or with one API call. Flow receives Meta’s webhooks and sends for you, so there is no webhook server for you to run.
Go live
Switch it on. The same project ships to iMessage, Telegram, ChatGPT and Claude when you want it there.

terminal

$ npx @flow-engineer/flow new my-agent
$ cd my-agent
$ npx @flow-engineer/flow test
✓ all scenarios passing

Already have an agent? Call the Flow Messaging API from any language instead.

Guide

WhatsApp AI agents, explained.

What is a WhatsApp AI agent?

A program that reads a customer’s WhatsApp messages, works out what they want with a language model, calls your systems (orders, bookings, accounts) and replies in the same chat. Unlike a menu bot, it handles free text, voice notes and photos, and it finishes the task instead of sending a link.

Is an AI chatbot allowed on WhatsApp in 2026?

Yes, for business tasks. Since 15 January 2026 WhatsApp’s Business terms bar general-purpose AI assistants (which is why consumer chatbots like ChatGPT left WhatsApp), but agents that serve your own customers, such as support, bookings, orders and sales, are allowed. Build the agent around your product’s jobs, which is what Flow’s tools are for.

WhatsApp Business API vs the WhatsApp Business app

The Business app runs on one phone and is meant for people replying by hand. An AI agent needs the WhatsApp Business Platform (the Cloud API), which receives messages by webhook and sends replies over HTTP. With Flow, you connect your Business Account’s number once and Flow handles the Cloud API’s webhooks, retries and the 24-hour window.

The 24-hour window and templates

When a customer messages you, you can reply freely for 24 hours. Messages outside that window, like reminders and order updates, must use templates WhatsApp has approved, and only to people who opted in. Flow checks the window for you and says when a template is needed.

How much does the WhatsApp API cost?

Meta charges per message by category (marketing, utility, authentication) and country, and rates change, so check Meta’s current pricing page. Flow’s own pricing is on the pricing section.

Can I build a WhatsApp chatbot with ChatGPT or Claude?

Yes: Flow lets you pick the model. The agent uses it to understand messages and decide which of your tools to call, so you can change models without rewriting the WhatsApp side.

FAQ

WhatsApp questions,
answered.

How do I get WhatsApp Business API access?

Through a Meta Business account and app, or through a provider. With Flow, you connect the number from your WhatsApp Business Account, and Flow handles the webhooks, retries and the 24-hour window.

Can I put an AI chatbot on WhatsApp in 2026?

Yes, if it serves your business: support, bookings, orders, sales. WhatsApp’s terms bar general-purpose AI assistants on the Business API since 15 January 2026.

Can I use my existing number?

Yes. Bring a number you own or get a new one through Flow. A number that is active on the regular WhatsApp app has to move off it first.

Can the agent message customers first?

Yes, customers who opted in, with WhatsApp-approved templates for reminders, updates and follow-ups. After they reply, it can talk freely for 24 hours.

Does it support buttons, voice notes and images?

Yes. Reply buttons and lists, images, documents and voice notes go both ways, with typing indicators, reactions and read receipts.

Which programming language do I use?

Flow Framework is TypeScript. If you already have an agent in another language, use the Flow Messaging API over REST instead.

Is the WhatsApp API free?

No. Meta charges per message by category and country. Check Meta’s pricing page for current rates.

Can the same agent run on iMessage and Telegram?

Yes. The same Flow project ships to WhatsApp, iMessage and Telegram, and as an MCP server and CLI for ChatGPT and Claude.

Put your agent on WhatsApp this week.

One open-source TypeScript project. The same agent on iMessage, Telegram, ChatGPT, Claude and more.

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