# What Database Technologies Are Commonly Used in Clone Projects: Insights from Clone-Wars

> Discover popular database technologies in clone projects like Firebase, MongoDB, PostgreSQL, and MySQL. Analyze tech stack data from the Clone-Wars repository.

- Repository: [Gourav Goyal/Clone-Wars](https://github.com/GorvGoyl/Clone-Wars)
- Tags: deep-dive
- Published: 2026-06-16

---

**Firebase, MongoDB, PostgreSQL, and MySQL dominate the database landscape in open-source clone projects, with Firebase appearing in approximately 30% of entries and MongoDB in roughly 20%, according to the tech-stack data curated in the GorvGoyl/Clone-Wars repository.**

The GorvGoyl/Clone-Wars repository aggregates over 100 open-source clones of popular web and mobile applications, providing a unique window into which database technologies are commonly used in clone projects. By analyzing the tech-stack column in the [`README.md`](https://github.com/GorvGoyl/Clone-Wars/blob/main/README.md) file, clear patterns emerge showing developers favor specific back-ends for rapid prototyping, real-time synchronization, and production-ready relational storage.

## The Dominant Database Technologies

Based on the curated list in [`README.md`](https://github.com/GorvGoyl/Clone-Wars/blob/main/README.md), four database technologies account for the majority of implementations across video streaming, social media, productivity, and communication clones.

### Firebase and Firestore: Real-Time Synchronization

**Firebase** (including Realtime Database and Firestore) appears in approximately **30% of entries**, making it the most prevalent choice. Its popularity stems from built-in authentication, real-time listeners, and schemaless document storage that accelerates mobile and web development.

- **Instagram clones** leverage *Firebase Firestore* for media-rich post storage and real-time comments (see entry at line 37 in [`README.md`](https://github.com/GorvGoyl/Clone-Wars/blob/main/README.md))
- **Todoist clones** utilize Firebase for rapid task synchronization across devices (line 40)
- **Netflix and YouTube clones** frequently employ Firebase for user watchlists and streaming metadata (lines 62 and 99)

### MongoDB: Flexible Document Storage

**MongoDB** accounts for roughly **20% of entries**, particularly prevalent in MERN-stack (MongoDB, Express, React, Node.js) projects requiring flexible schemas for unstructured data.

- **Dribbble clones** store design portfolios and user interactions in MongoDB (line 92)
- **TikTok clones** built with React Native use MongoDB for video metadata and user relationships (line 207)
- **Stack Overflow and Trello clones** in the MERN ecosystem list MongoDB as their primary data store (lines 200 and 221)

### PostgreSQL: ACID-Compliant Relational Data

**PostgreSQL** appears in approximately **15% of entries**, often paired with **Prisma** ORM or Supabase for type-safe, complex relational queries requiring strict ACID guarantees.

- **Airbnb clones** implement Prisma with PostgreSQL for booking management and user roles (line 63)
- **Calendly clones** use Prisma-generated PostgreSQL schemas for calendar events and availability windows (line 80)
- **Supabase-based clones** explicitly list PostgreSQL as their underlying database, offering auto-generated APIs and row-level security (lines 101 and 102)

### MySQL: Traditional Relational Infrastructure

**MySQL** maintains a **15% share**, powering PHP/Laravel, Django, and traditional full-stack clones where mature relational features and hosting compatibility are priorities.

- **Bit.ly-style Polr** projects use MySQL for URL shortening and click analytics (line 73)
- **Discord clones** built with Node.js and Express store server configurations and message history in MySQL (line 85)
- **Mastodon and email service clones** rely on MySQL for federated social data and mailbox storage (lines 142 and 144)

### Specialized and Emerging Options

**SQLite** appears occasionally (~5%) in lightweight, desktop-style applications such as **Fosscord** (a Discord alternative) for local credential and settings storage (line 87).

**Redis** appears rarely, serving as an in-memory cache and pub/sub layer for real-time features in **ActivityPub** implementations like the Reddit-like *pyfedi* project (line 175).

**Supabase** (PostgreSQL-based) represents an emerging trend, offering a drop-in Firebase alternative for modern clones requiring both relational integrity and real-time subscriptions (line 101).

**RethinkDB** and **DynamoDB** appear in specialized use-cases, such as the **Tinode** chat server which lists RethinkDB alongside MongoDB for real-time collaboration (line 162).

## Implementation Examples from the Source

The following snippets demonstrate how developers configure these databases in clone projects, reflecting patterns found in the [`README.md`](https://github.com/GorvGoyl/Clone-Wars/blob/main/README.md) entries.

### Firebase Firestore Setup

Used in Instagram clones (line 37):

```javascript
import { initializeApp } from "firebase/app";
import { getFirestore, collection, getDocs } from "firebase/firestore";

const firebaseConfig = {
  apiKey: "YOUR_API_KEY",
  projectId: "your-app",
  // …other keys…
};

const app = initializeApp(firebaseConfig);
const db = getFirestore(app);

// Fetch posts for a social media feed
async function loadPosts() {
  const snapshot = await getDocs(collection(db, "posts"));
  return snapshot.docs.map(doc => ({ id: doc.id, ...doc.data() }));
}

```

### MongoDB with Mongoose

Used in Dribbble clones (line 92):

```javascript
const mongoose = require("mongoose");

mongoose.connect("mongodb://localhost:27017/clone-db", {
  useNewUrlParser: true,
  useUnifiedTopology: true,
});

const postSchema = new mongoose.Schema({
  author: String,
  imageUrl: String,
  caption: String,
  createdAt: { type: Date, default: Date.now },
});

const Post = mongoose.model("Post", postSchema);

async function createPost(data) {
  const post = new Post(data);
  await post.save();
  return post;
}

```

### PostgreSQL with Node.js

Used in Airbnb clones via Prisma (line 63):

```javascript
const { Pool } = require("pg");

const pool = new Pool({
  user: "postgres",
  host: "localhost",
  database: "clone",
  password: "secret",
  port: 5432,
});

async function getUsers() {
  const { rows } = await pool.query("SELECT id, username FROM users");
  return rows;
}

```

### MySQL with mysql2

Used in Bit.ly-style Polr projects (line 73):

```javascript
const mysql = require("mysql2/promise");

const connection = await mysql.createConnection({
  host: "localhost",
  user: "root",
  database: "clone_db",
  password: "secret",
});

async function listLinks() {
  const [rows] = await connection.execute("SELECT * FROM links");
  return rows;
}

```

### SQLite with better-sqlite3

Used in Fosscord (line 87):

```javascript
const Database = require("better-sqlite3");
const db = new Database("clone.db");

function getSettings() {
  return db.prepare("SELECT key, value FROM settings").all();
}

```

## Why These Technologies Dominate Clone Projects

The concentration of Firebase, MongoDB, PostgreSQL, and MySQL in the Clone-Wars repository reflects three key developer priorities:

- **Rapid prototyping** – Firebase and MongoDB offer schemaless data models that let developers focus on UI/UX rather than schema migrations during early development phases.
- **Mature ecosystems** – PostgreSQL and MySQL provide robust relational features, ACID compliance, and extensive tooling for complex business logic such as payments, user roles, and audit trails.
- **Framework integration** – Prisma pairs naturally with Next.js and TypeScript for PostgreSQL projects, while Mongoose remains the de-facto driver for Express-based MongoDB backends, creating efficient full-stack development workflows.

## Summary

The GorvGoyl/Clone-Wars repository reveals distinct database preferences across 100+ open-source clones:

- **Firebase/Firestore** leads adoption (~30%) for real-time mobile and web applications requiring instant synchronization.
- **MongoDB** captures ~20% of projects, dominating the MERN stack for flexible, document-oriented storage.
- **PostgreSQL** and **MySQL** each hold ~15% market share, with PostgreSQL trending toward modern Prisma/Supabase stacks and MySQL remaining prevalent in PHP and Django ecosystems.
- **SQLite** and **Redis** serve niche use cases requiring lightweight file-based storage or in-memory caching, respectively.
- **Supabase** represents an emerging PostgreSQL-based alternative to Firebase for real-time relational applications.

## Frequently Asked Questions

### What is the most popular database technology for clone projects?

**Firebase and Firestore** appear most frequently in the Clone-Wars repository, utilized in approximately 30% of entries including Instagram, Netflix, and YouTube clones. Its dominance stems from integrated authentication, real-time listeners, and serverless architecture that reduce backend development time.

### Why do developers choose MongoDB for clone projects?

Developers select **MongoDB** for roughly 20% of clones because its document-oriented model accommodates flexible schemas ideal for social media feeds, design portfolios, and content management systems. The technology pairs naturally with Express and React in the popular MERN stack, allowing rapid iteration without rigid database migrations.

### When should I use PostgreSQL instead of Firebase for a clone?

Choose **PostgreSQL** when your clone requires complex relational queries, strict ACID compliance, or multi-table transactions—common in booking systems like Airbnb clones or calendar apps like Calendly alternatives. According to the repository data (lines 63 and 80), PostgreSQL excels when paired with Prisma ORM for type-safe database access in TypeScript projects.

### How does the Clone-Wars repository track database technologies?

The repository maintains a central markdown table in [`README.md`](https://github.com/GorvGoyl/Clone-Wars/blob/main/README.md) that lists each clone alongside its tech stack, including database technologies. This structured format allows analysis of adoption patterns acrosslines 37, 63, 73, 92, and others, revealing that Firebase, MongoDB, PostgreSQL, and MySQL constitute the majority of backend choices documented in the curated list.