Embedded Signup | Muchaw DEV

Embedded Signup is a Facebook-native flow that lets your end-users connect their WhatsApp Business numbers directly from your application — without any Meta Business Manager knowledge. It opens a popup using the Facebook JavaScript SDK, guides the user through authorization, and returns an authorization code.

Muchaw DEV handles the entire backend provisioning process. Your end-user never knows Muchaw DEV exists.

Flow overview

Your Frontend         Muchaw DEV              Meta Cloud API
     │                     │                       │
     │  GET /init          │                       │
     │────────────────────▶│                       │
     │ { app_id, config_id }                       │
     │◀────────────────────│                       │
     │                     │                       │
     │  FB.login(app_id, config_id)                │
     │──────────────────────────────────────────▶  │
     │              (user completes popup)          │
     │◀──────────────────────────────────────── code│
     │                     │                       │
     │  POST /complete     │                       │
     │  { code }           │                       │
     │────────────────────▶│                       │
     │                     │  Register, configure  │
     │                     │──────────────────────▶│
     │  { number_id, status: "PENDING" }           │
     │◀────────────────────│                       │
     │                     │                       │
     │  [webhook: number.activated fires]          │

Integration steps

1. Fetch SDK config

1 const res = await fetch("https://dev.muchau.com.br/api/embedded-signup/init", {
2   headers: { Authorization: `Bearer ${apiKey}` },
3 });
4 const { app_id, config_id } = await res.json();

1 <script>
2   window.fbAsyncInit = function() {
3     FB.init({ appId: app_id, version: "v21.0" });
4   };
5 </script>
6 <script async src="https://connect.facebook.net/en_US/sdk.js"></script>

1 FB.login(
2   (response) => {
3     if (response.authResponse?.code) {
4       completeSignup(response.authResponse.code);
5     }
6   },
7   {
8     config_id: config_id,
9     response_type: "code",
10     override_default_response_type: true,
11   }
12 );

1 async function completeSignup(code) {
2   const res = await fetch("https://dev.muchau.com.br/api/embedded-signup/complete", {
3     method: "POST",
4     headers: {
5       Authorization: `Bearer ${apiKey}`,
6       "Content-Type": "application/json",
7     },
8     body: JSON.stringify({ code }),
9   });
10   const { number_id, status } = await res.json();
11   // Status is "PENDING" — wait for the number.activated webhook
12 }

4. Wait for activation

Configure a webhook for number.activated to know when the number is ready:

1 {
2   "event": "number.activated",
3   "data": {
4     "id": "clxyz123...",
5     "displayNumber": "+55 11 99999-0000",
6     "status": "ACTIVE"
7   }
8 }

White-label

The entire Embedded Signup flow uses Muchaw DEV’s Meta App and Business Portfolio internally. Your end-user sees only standard Facebook UI — there is no mention of Muchaw DEV. You can customize the experience by embedding it inside your own product UI.

Requirements

Your frontend must be served over HTTPS (Facebook requires this)
The domain must be added to the Muchaw DEV allowed domains list (contact support)

What is Embedded Signup?