Facebook Messenger (now often referred to as Messenger) is a free messaging app and platform developed by Meta (formerly Facebook). It was originally launched in 2011 as a standalone app separate from the Facebook main app. Messenger allows users to send text messages, make voice and video calls, share media, and even send money through Meta Pay.

Key Features of Facebook Messenger

✅ Instant Messaging – Send text messages, GIFs, stickers, and emojis.
✅ Voice & Video Calls – High-quality 1-on-1 and group calls (supports up to 50 people in a room).
✅ End-to-End Encryption – Secure messaging and calls for private chats.
✅ Messenger Rooms – A feature similar to Zoom for large group video chats.
✅ AI & Chatbots – Businesses use AI chatbots for customer service and automation.
✅ Stories & Vanish Mode – Share disappearing messages and status updates.
✅ Multi-Platform Support – Works on iOS, Android, Web, and Desktop apps.
✅ Integration with Facebook & Instagram – Users can chat across apps without switching.
✅ Meta Pay – Send and receive money securely within the app.

Facebook Messenger is a messaging app that supports text, voice, video calls, and payments. It is built using multiple programming languages for different parts of the system:

1. Frontend (Mobile & Web)

• Swift & Objective-C – Used for the iOS app development.
• Java & Kotlin – Used for the Android app development.
• React (JavaScript/TypeScript) – Used for the Messenger Web application.

2. Backend & Infrastructure

• Hack (HHVM – HipHop Virtual Machine) – A custom PHP-based language developed by Meta for high-performance backend development.
• Python – Used for AI, chatbots, and machine learning functionalities.
• Erlang – Used for handling real-time messaging and maintaining persistent connections.
• C++ – Used for performance-critical tasks, such as encryption, data compression, and low-latency messaging.
• Java & Go (Golang) – Used in various backend microservices for scalability and efficiency.

3. Database & Storage

• MySQL & RocksDB – Used for storing chat history and user data.
• Apache Cassandra – A distributed database used for handling large-scale data storage.

4. AI & Machine Learning

• PyTorch & TensorFlow – Used for AI-driven features like smart replies, chatbots, and voice recognition.

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5. Networking & Infrastructure

• GraphQL – Meta’s query language for efficient data fetching.
• Apache Kafka – Used for real-time data streaming and event handling.
• Thrift – A cross-language framework used for efficient service communication.

Conclusion

Messenger is built with a mix of modern and legacy technologies to ensure real-time communication, scalability, and high performance. Meta continues to evolve Messenger with AI-driven features, encryption, and integrations with WhatsApp, Instagram, and Meta’s ecosystem.