1. Install Node.js: Make sure you have Node.js installed on your machine, as you'll be using it to run scripts that interact with Firebase and MongoDB.

2. Install Firebase CLI: Install the Firebase CLI to interact with Firebase from the command line. You can install it via npm:

   ```

   npm install -g firebase-tools

   ```

3. Install MongoDB: Ensure MongoDB is installed and running on your local machine or server. You can download it from the MongoDB official website.

4. Install MongoDB Driver: Install the official MongoDB Node.js driver to allow your script to interact with your MongoDB instance:

   ```

   npm install mongodb

   ```

1. Authenticate Firebase CLI: Authenticate with Firebase using the CLI:

   ```

   firebase login

   ```

2. Access Your Firebase Project: Navigate to your Firebase project directory or initialize a new one:

   ```

   firebase init

   ```

3. Export Data: Export your Firebase Realtime Database data to a JSON file:

   ```

   firebase database:get / > firebase-export.json

   ```

The exported data will be in JSON format. You may need to transform this data into a format that's suitable for MongoDB, especially if your data is deeply nested or not structured in the way MongoDB expects.

1. Write a Script to Transform Data: Create a Node.js script that reads the exported JSON file, transforms the data into the desired structure, and saves it to a new JSON file. Here's a simple example:

   ```javascript

   const fs = require('fs');

   let rawData = fs.readFileSync('firebase-export.json');

   let firebaseData = JSON.parse(rawData);

   // Transform the data here according to your needs

   let transformedData = transformData(firebaseData);

   fs.writeFileSync('transformed-data.json', JSON.stringify(transformedData));

   function transformData(data) {

     // Your transformation logic

     return data;

   }

   ```

1. Write a MongoDB Import Script: Create a script that reads the transformed JSON file and imports it into MongoDB.

   ```javascript

   const MongoClient = require('mongodb').MongoClient;

   const fs = require('fs');

   let rawData = fs.readFileSync('transformed-data.json');

   let dataToImport = JSON.parse(rawData);

   const url = 'mongodb://localhost:27017';

   const dbName = 'myDatabase'; // Replace with your database name

   const collectionName = 'myCollection'; // Replace with your collection name

   MongoClient.connect(url, { useNewUrlParser: true, useUnifiedTopology: true }, (err, client) => {

     if (err) throw err;

     console.log(""Connected to MongoDB!"");

     const db = client.db(dbName);

     const collection = db.collection(collectionName);

     collection.insertMany(dataToImport, (err, result) => {

       if (err) throw err;

       console.log(`Inserted ${result.insertedCount} documents`);

       client.close();

     });

   });

   ```

2. Run the Import Script: Execute your script to import the data into MongoDB.

   ```

   node mongo-import.js

   ```

1. Check MongoDB: Use the MongoDB shell or a GUI tool like MongoDB Compass to verify that the data has been imported correctly.

2. Query the Data: Run some queries to ensure that the data looks right and is structured as you expect.

1. Remove Temporary Files: Once the import is verified, you can remove any temporary files that were created during the process, such as the exported JSON file from Firebase and any transformed data files.

2. Secure Your Data: Ensure that your MongoDB instance is secured and that proper access controls are in place to protect your data.

By following these steps, you should be able to successfully move data from Firebase Realtime Database to MongoDB without using third-party connectors or integrations. Remember to back up your data before performing operations like these to prevent any potential data loss.

‍