> ## Documentation Index
> Fetch the complete documentation index at: https://moengage-sdk-docs.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Real-time Uninstall Tracking

# What is real-time uninstall tracking?

Real-time uninstall tracking enables you to track the uninstall immediately after the user uninstalls an app integrated with *Firebase Analytics*.

The Firebase tracks the event **app-remove** when an app is uninstalled. The **app-remove** event is used by MoEngage using Firebase Cloud Functions.

# What are Firebase Cloud Functions?

Cloud Functions for Firebase is a serverless framework that programmatically provides responses to events triggered by Firebase features and HTTPS requests. For more information, refer to [Cloud Functions for Firebase](https://firebase.google.com/docs/functions).

# How is real-time uninstall tracking different from the existing uninstall tracking?

The current uninstall tracking in MoEngage happens by sending Silent Push notifications once a day to all user devices. Up to 24 hours is required to track uninstall.

Using the real-time uninstall tracking, the uninstall is tracked immediately by the Firebase SDK so that you can respond quickly to user uninstalls

# Implementation of real-time uninstall tracking

<Check>
  Ensure you have the Firebase Blaze plan account.

  To deploy Cloud Functions to the runtime environment, your project must be on the [Firebase pricing plan](https://firebase.google.com/pricing).
</Check>

## Set up a common identifier

Ensure your app has integrated Firebase Analytics SDK. For more information, refer to [Get started with Google Analytics](https://firebase.google.com/docs/analytics/get-started).

Add the following code in your app to set up a common identifier between MoEngage and Firebase.

<CodeGroup>
  ```kotlin Kotlin theme={"theme":{"light":"github-light","dark":"github-dark"}}
  val firebaseAnalytics = FirebaseAnalytics.getInstance(this)
  MoEHelper.getInstance(this).setUniqueId("<unique-id>")
  firebaseAnalytics.setUserProperty("MOE_USER_ATTRIBUTE_UNIQUE_ID", "<unique-id>")
  }
  ```
</CodeGroup>

**Note:** The following values are not allowed in the UniqueID field: "unknown", "guest", "null", "0", "1", "true", "false", "user\_attribute\_unique\_id", "(empty)", "na", "n/a", "", "dummy\_seller\_code", "user\_id", "id", "customer\_id", "uid", "userid", "none", "-2", "-1", "2"

## Set up the conversion event using Firebase

<Check>
  Ensure that the App is integrated with Firebase Analytics for real-time uninstall tracking.
</Check>

Firebase analytics automatically collects the event `app_remove`. The `app_remove` event is, an Android-only event, tracked when an application package is removed or uninstalled from the device, regardless of the installation source. To set up a real-time uninstall make sure that the `app_remove` event is marked as the conversion event on the Firebase dashboard.

To set up a conversion event, follow these steps:

1. Navigate to [Firebase Console](https://console.firebase.google.com/) and select the Firebase project integrated with the app.
2. From the Firebase dashboard, select **Analytics > Events**.
3. Enable the ***Mark as Conversion*** toggle for **app\_remove** event in the event list.

## Create Cloud Function

After the conversion event is set up, use the [Cloud Function for Firebase](https://firebase.google.com/docs/functions/get-started) to create a function and send the **app\_remove** event to MoEngage.

To create and publish a cloud function using Node JS, follow these steps:

1. Install [Node.js](https://nodejs.org/en/) and [npm](https://www.npmjs.com/).\
   Node.js environment is required to write functions. Use the Firebase CLI to deploy functions to the Cloud Functions runtime.
2. Install Firebase CLI using the following code:

<CodeGroup>
  ```CLI CLI Command theme={"theme":{"light":"github-light","dark":"github-dark"}}
  npm install -g firebase-tools
  ```
</CodeGroup>

3. Run ***firebase login*** to log in using the browser and authenticate the firebase tool.
4. Navigate to your Firebase project directory.
5. Run ***firebase init functions***.
6. Select ***Javascript*** as a language option.
7. Add the following code to the **index.js** file:

<CodeGroup>
  ```javascript index.js theme={"theme":{"light":"github-light","dark":"github-dark"}}
  "use strict";

  const functions = require("firebase-functions");
  const admin = require("firebase-admin");
  const https = require("https");
  require("firebase-functions/lib/logger/compat");

  admin.initializeApp();

  exports.sendAndroidUninstallToMoEngage = functions.analytics.event("app_remove")
      .onLog((event) => {
        console.log("sendAndroidUninstallToMoEngage() : Event is: " +
        JSON.stringify(event));
        return exports.sendAppUninstallEventData(event);
      });

  exports.sendAppUninstallEventData = function(event) {
  //fetch the unique ID <MOE_USER_ATTRIBUTE_UNIQUE_ID>
  var uniqueId = event.user.userProperties.MOE_USER_ATTRIBUTE_UNIQUE_ID.value;
  //send event using S2S API of MoEngage
  //https://developers.moengage.com/hc/en-us/articles/4404674776724-Data-API#user-api-0-10
  };
  ```
</CodeGroup>

8. Add the following code to **package.json** file:

<CodeGroup>
  ```json pacakage.json theme={"theme":{"light":"github-light","dark":"github-dark"}}
  {
    "name": "functions",
    "description": "Cloud Functions for Firebase",
    "scripts": {
      "lint": "eslint .",
      "serve": "firebase emulators:start --only functions",
      "shell": "firebase functions:shell",
      "start": "npm run shell",
      "deploy": "firebase deploy --only functions",
      "logs": "firebase functions:log"
    },
    "engines": {
      "node": "12"
    },
    "main": "index.js",
    "dependencies": {
      "firebase-admin": "^10.0.0",
      "firebase-functions": "^3.16.0",
      "firebase-tools": "^9.23.0",
      "g": "^2.0.1",
      "requestretry": "^4.1.1"
    },
    "devDependencies": {
      "eslint": "^7.6.0",
      "eslint-config-google": "^0.14.0",
      "eslint-plugin-promise": "^4.0.1",
      "firebase-functions-test": "^0.2.0",
      "requestretry": "^4.1.1",
      "web-push": "^3.4.5"
    },
    "private": true
  }
  ```
</CodeGroup>