# Research: Everyone Connects Their Phone – One URL vs Full URL Per User **Your goal:** Each person connects their own phone number to your Meta API; your system should support that and (you said) “create a full URL for that user.” Below is what the WhatsApp Cloud API allows and the two main ways you can build this. --- ## 1. How Meta’s model works - **One Meta App** (yours) has **one default webhook URL** in the App Dashboard. - **Multiple businesses** can use your app: each has a **WhatsApp Business Account (WABA)** and can add **phone numbers** (typically 1–2 per WABA). - **“Everyone connect their phone”** is done via **Embedded Signup**: your app embeds Meta’s flow so each user/business registers their number and gets a WABA (or adds a number to an existing WABA). You get **Phone Number ID** and **WABA ID** (and tokens) for each. - **Incoming messages** always go to a **webhook**. Who receives them is determined by: - **Default:** All messages for all numbers in your app go to the **one app-level callback URL**. - **Override (optional):** You can set a **different callback URL per WABA** or **per phone number**. Meta sends to that URL instead of the app default for that WABA/number. So you have two high-level options: **one shared URL** (route by `phone_number_id` inside your backend) or **one “full” URL per user** (using Meta’s webhook override). --- ## 2. Option A: One webhook URL – route by `phone_number_id` (no per-user URL) **Idea:** Keep a **single** webhook URL for the whole app. Every user’s messages hit that URL. Your backend uses the payload to know which user/business it is. **How it works:** - In the App Dashboard you set **one** “Callback URL” (e.g. `https://api.yours.com/api/v1/webhooks/whatsapp`). - Every incoming message from **any** number connected to your app is sent to that URL. - Each webhook payload includes **`metadata.phone_number_id`** (and WABA id in the object hierarchy). You already use this in `extractBusinessId` to look up which business the message belongs to. - So: **one URL**, many users; you **route internally** by `phone_number_id` → business (e.g. in DB: `api_keys.phone_number_id` → `integrations.business_id`). **Pros:** - Simple: one URL to maintain and verify. - No need to register or change URLs when a new user connects. - Matches how many multi-tenant WhatsApp apps work. - Your current code (one webhook + `phone_number_id` → business) already fits this. **Cons:** - You do **not** “create a full URL for that user” – there is only one URL; routing is by payload, not by URL path. **Best for:** “One app, many businesses; we don’t need a unique URL per user, we just need to know which business each message belongs to.” --- ## 3. Option B: “Full URL” per user – webhook override (unique URL per WABA/number) **Idea:** When a user connects their number, **your system creates a dedicated webhook URL for that user** and tells Meta to send that user’s messages **only** to that URL (via **webhook override**). **How it works:** - **Default:** App still has one URL in the dashboard (required by Meta). - **Override:** When a user completes Embedded Signup and you get their WABA (or phone number), you call Meta’s API to set an **alternate callback** for that WABA or that phone number: - **Per WABA:** `POST /{WABA_ID}/subscribed_apps` with `override_callback_uri` and `verify_token`. - **Per phone number:** use the phone number override API with `override_callback_uri`. - You choose the URL format, for example: - `https://api.yours.com/webhooks/wa/{business_id}` - or `https://api.yours.com/webhooks/wa/{waba_id}` - Meta will then send messages for **that** WABA/number to **that** URL. Your backend can: - Either use the **path** (e.g. `business_id`) to know the tenant and process the same payload you process today, or - Keep a single handler and still use `phone_number_id` from the payload (override only changes where the request is sent, not the payload). **Pros:** - You literally “create a full URL for that user” and register it with Meta. - Can be useful for very strict isolation, custom routing, or per-tenant logging/monitoring by URL. - Fits the mental model “each user has their own webhook endpoint.” **Cons:** - More moving parts: you must call the override API when a user connects (and optionally clear it when they disconnect). - Each override URL must respond to Meta’s **GET verification** (same `hub.mode`, `hub.verify_token`, `hub.challenge`); you can do that with one route that reads tenant from path and uses a shared or per-tenant verify token. - Slightly more to document and operate (list overrides, handle failures, etc.). **Best for:** “We want each user to have their own distinct webhook URL that our system creates and registers with Meta.” --- ## 4. How “everyone connect their phone” works in both options - **Embedded Signup** is the way “everyone” connects their number to **your** Meta app. You embed Meta’s UI; the user registers a number and (optionally) a WABA. Your backend gets: - WABA ID - Phone Number ID - Access token (and possibly system user / permissions) - You store these per **business** (or per user) in your DB (e.g. `integrations` + `api_keys`), so you can: - **Send** messages (using that phone’s Phone Number ID and token). - **Receive** messages: either at one URL (Option A) or at a per-user override URL (Option B). So “everyone connect their phone number to our Meta API” is the same in both options; the only difference is whether you use **one webhook URL** or **one full URL per user** (override). --- ## 5. Summary and recommendation | Aspect | Option A: One URL | Option B: Full URL per user (override) | |--------|-------------------|----------------------------------------| | Webhook | Single app URL | One URL per WABA/number (override) | | Who decides tenant? | Backend via `phone_number_id` in payload | Backend via path (e.g. `business_id`) or still `phone_number_id` | | “Create a full URL for that user” | No | Yes – you generate and set it via API | | Complexity | Lower | Higher (override API, verification per URL) | | Your current code | Already aligned | Needs override flow + route(s) for override URLs | - If you **don’t** need a distinct URL per user and only need “everyone can connect their number and we route correctly,” **Option A** is enough and you mainly need to add **Embedded Signup** and store Phone Number ID + token per business. - If you **do** want “our system creates a full URL for that user” and registers it with Meta, use **Option B**: when a user connects their number, create a URL (e.g. `https://api.yours.com/webhooks/wa/{business_id}`), call Meta’s **webhook override** API for that WABA or phone number, and handle GET/POST on that path (same payload shape; optionally route by path). --- ## 6. References (Meta) - [Webhooks](https://developers.facebook.com/docs/whatsapp/cloud-api/webhooks/) – default app callback. - [Webhook overrides](https://developers.facebook.com/docs/whatsapp/cloud-api/webhooks/override/) – per-WABA and per–phone-number alternate callback URL. - [Embedded Signup](https://developers.facebook.com/docs/whatsapp/embedded-signup/) – onboard businesses and let them connect their numbers to your app. - [Business phone numbers](https://developers.facebook.com/docs/whatsapp/cloud-api/phone-numbers) – add/manage numbers under a WABA. Once you decide between “one URL for all” (A) or “full URL per user” (B), the next step is to design the exact override URL shape and the Embedded Signup flow (when to call override, how to store and display the “full URL” for that user).