How is WhatsApp written - briefly?
WhatsApp is primarily written in Erlang for the server-side components and in Objective-C for iOS, Java for Android, and C# for Windows Phone on the client side.
How is WhatsApp written - in detail?
WhatsApp, one of the most popular messaging platforms worldwide, was developed by Brian Acton and Jan Koum in 2009. The application's initial focus was on providing users with a seamless and reliable messaging experience, differentiating it from traditional SMS services that were often plagued by high costs and limited functionality.
The development of WhatsApp began with a simple yet powerful idea: to create a cross-platform messaging application that could run efficiently on various operating systems, including iOS and Android. The founders recognized the potential of smartphones and sought to leverage their capabilities to enhance communication. They started by writing the initial code for WhatsApp using the Erlang programming language, which is known for its ability to handle a large number of simultaneous connections with low latency—a crucial requirement for real-time messaging applications.
As the application gained traction and more users joined the platform, it became evident that scaling the infrastructure would be necessary to maintain performance and reliability. To achieve this, WhatsApp's engineers implemented a combination of distributed systems and cloud-based technologies. They employed a horizontally scalable architecture, allowing the system to handle an increasing number of users without significant degradation in service quality. This approach involved distributing the workload across multiple servers, ensuring that no single server became a bottleneck.
WhatsApp also relies heavily on end-to-end encryption to ensure the privacy and security of user communications. The implementation of this feature was a significant technological achievement, as it required sophisticated cryptographic algorithms to encrypt messages on the sender's device and decrypt them only on the recipient's device. This ensures that even WhatsApp itself cannot access the contents of users' messages, providing a high level of security and trust among its user base.
In addition to messaging, WhatsApp has expanded its functionality to include voice and video calls, file sharing, and other features. These additions required careful integration into the existing codebase, ensuring that new functionalities did not compromise the performance or stability of the core messaging service. The development team at WhatsApp continues to innovate, regularly updating the application with new features and improvements based on user feedback and technological advancements.
In conclusion, WhatsApp's success can be attributed to its founders' vision of creating a reliable and efficient messaging platform, as well as the robust infrastructure and advanced technologies that support it. The application's codebase has evolved over the years to include sophisticated features such as end-to-end encryption and real-time communication capabilities, all while maintaining a user-friendly interface and high performance standards.