Learn how to fix Firebase Realtime Database insecure rules, why security matters, and best practices to protect your data from unauthorized access.

If you’ve received a warning from Firebase stating that your Realtime Database has insecure rules, you’re not alone. Many developers overlook Firebase security rules, leaving their databases vulnerable to attacks.

[Firebase] Your Realtime Database ‘app-name-auth-default-rtdb’ has insecure rules,
any user can write to your entire database, any logged-in user can read your entire database

Firebase’s alert indicates that:

• Any user can write to your entire database
• Any logged-in user can read your entire database

This means your data is at risk of being stolen, modified, or deleted. In this guide, we’ll explore Firebase security rules, why they matter, and how to fix insecure configurations.

You’re not alone. Many developers face this issue when integrating firebase to their new app and just focusing on the integrating working without deep security focus.

What is Firebase?

Firebase is a Backend-as-a-Service (BaaS) platform by Google that provides tools for building web and mobile apps. It includes services like:

• Firebase Authentication – (user sign-up and login)
• Firestore & Realtime Database – for storing data
• Cloud Functions – for running backend code (Serverless backend logic)
• Firebase Hosting – for deploying web apps
• Storage (File storage)
• Firebase Analytics, Crashlytics, and more

Firebase eliminates the need for traditional server management, allowing developers to focus on building apps quickly.

What Are Firebase Security Rules?

Firebase Security Rules are a set of permissions that control who can read and write data in your Realtime Database, Firestore, or Storage. These rules act as a security layer between your app and your database.

Basic Structure of Firebase Rules

For the Realtime Database, rules are written in JSON-like syntax:

 

{
  "rules": {
    ".read": "auth != null",  // Only authenticated users can read
    ".write": "auth != null"  // Only authenticated users can write
  }
}

This rule means only authenticated (logged-in) users can read or write to the database.

For Firestore, rules use a different syntax:

rules_version = '2';
service cloud.firestore {
  match /databases/{database}/documents {
    match /{document=**} {
      allow read, write: if request.auth != null;
    }
  }
}

Firebase Realtime Database Insecure Rules

Firebase Realtime Database Insucure Rules can be very hard to fix or solve if you don’t understand how to set the proper rules for your app. Your rules don’t necessarily have to be too strict else you will block out users or admin from been able to access or modify their own data.

One of the best firebase rule logic is to limit users with “user” role to access only their own data and admin role to have greater access to data like write and reading of data. The only exception to this is, in the case of leaderboard when you want to display all user rankings.

Why Do We Use Firebase?

Without proper security rules:

• Malicious users can overwrite or delete your data.
• Unauthorized access can lead to data breaches.
• Excessive read/writes can increase Firebase costs.

Firebase does not enforce security by default—you must configure rules manually.

Firebase is popular because it helps developers:

• Build real-time apps fast
• Sync data across devices
• Focus on frontend without backend setup
• Authenticate users easily
• Store and retrieve data in real-time

Firebase is used for apps like chat apps, to-do lists, quizzes, eCommerce platforms, and many mor

Understanding Firebase Insecure Rules

The warning:

“Your Realtime Database has insecure rules: any user can read/write your entire database.”

Means your rules are too permissive, such as:

{
  "rules": {
    ".read": true,  // Anyone can read
    ".write": true  // Anyone can write
  }
}

Why Is This Dangerous?

• Data theft: Anyone can query your entire database.
• Data corruption: Attackers can delete or modify records.
• Financial risks: Excessive reads/writes can lead to high Firebase bills
• Attackers can delete your entire database
• Anyone can add spam or garbage data
• Unexpected read/write operations can lead to cost spikes

Firebase Rules: Test Mode vs. Production Mode

When setting up Firebase, you will be asked to choose from two rules mode:

1. Test Mode (Default for New Projects)

{
  "rules": {
    ".read": true,  
    ".write": true  
  }
}

• Allows open access during development. (Never use this in production!)
• For trying out features quickly
• Open access to everyone
• Not suitable for real users or live apps

2. Production Mode (Locked Down Rules)

{
  "rules": {
    ".read": "auth != null",
    ".write": "auth.uid === 'admin_uid'"  
  }
}

• Restricts access to authenticated users.
• Grants write access only to admins.

Best Practice: Always switch to production mode before launching your

Firebase Security Rules Explanation 101

Let’s break down this Firebase Realtime Database rule line by line so you fully understand what each part does:

{
  "rules": {
    "users": {
      "$uid": {
        ".read": "$uid === auth.uid",
        ".write": "$uid === auth.uid"
      }
    }
  }
}

Now let’s go line-by-line:

1. “rules”: {

• This is the root of your Firebase Realtime Database security rules.
• Everything inside this object defines how different parts of the database can be read from or written to.

2. “users”: {

• This matches a node in your database called “users”.
• For example, in your data you might have something like:

“users”: {
“abc123”: { “name”: “John” },
“xyz456”: { “name”: “Jane” }
}

3. “$uid”: {

• This is a wildcard variable. It matches any user ID under the “users” node.
• So “$uid” will represent “abc123”, “xyz456”, or whatever the authenticated user’s UID is.
• This allows you to apply the same rules dynamically for each user.

 

READ ALSO: HOW TO SECURE YOUR WORDPRESS WEBSITE

4. “.read”: “$uid === auth.uid”,

This line says: allow read access only if the user is trying to read their own data. $uid is the user id from the database path which is usually automatomatically generated.

• auth.uid is the UID of the currently authenticated user.
• If both match (i.e., you’re reading your own data), then access is allowed. Otherwise, it’s denied.

5. “.write”: “$uid === auth.uid”

• Same logic as above, but for writing data.
• It ensures that a user can only write to their own record and not someone else’s.
• This prevents one user from modifying another user’s data.

In summary:

• Each user can only read/write their own data inside /users/{uid}.
• They can’t touch other users’ records.
• This is one of the most common and secure patterns for apps with user profiles.

Use Case Example: Firebase Rules for Login and Sign-Up App

If you’re building an app where users can register and manage their profiles, your database might look like this:

Scenario:

• Users can sign up & log in.
• Each user has a private profile (/users/{userId}).
• Admins can edit all profiles.

Firebase Database Secure Rules Example

{
  "rules": {
    "users": {
      "$userId": {
        ".read": "auth != null && auth.uid === $userId",  
        ".write": "auth != null && (auth.uid === $userId || auth.token.isAdmin === true)"  
      }
    }
  }
}

Explanation:

• Users can only read their own data.
• Users can edit their own data.
• Admins (isAdmin: true) can edit any user’s data.

How to Fix Firebase Realtime Database Insecure Rules

1. Open your Firebase console.
2. Navigate to Realtime Database > Rules.
3. Replace the insecure rules with proper conditions based on your data structure.
4. Use Firebase’s Rules Playground to test access.
5. Publish the rules once confirmed.

Importance of Secure Firebase Rules

• Data Privacy: Keep users’ info safe
• System Integrity: Only allow valid users to write valid data
• Cost Control: Protect your Firebase bill from abusive traffic
• Scalability: Build apps that scale securely
• Compliance: Helps with GDPR or legal data protection needs

Conclusion

Firebase is powerful, but with great power comes great responsibility. If you’re using Realtime Database, don’t stay in test mode forever.

Take time to apply production-ready rules, protect your app from unnecessary exposure, and build trust with your users.