How Facebook is not using PHP by still using PHP?

Facebook’s Technology Stack: A Deep Dive

Introduction

Facebook, as one of the leading giants in the tech industry, has always been at the forefront of innovation, particularly when it comes to its technology stack. In this comprehensive exploration, we’ll delve into the various components that make up Facebook’s technology stack, including its use of PHP, its alternative versions, and how they have improved performance and reliability.

1. The Role of PHP at Facebook

At the core of Facebook’s technology stack lies PHP, a popular scripting language. However, Facebook’s use of PHP is not as straightforward as it may seem. The company employs PHP for various purposes, but it doesn’t serve as the backbone of its core system. Instead, PHP is utilized in different ways within Facebook’s ecosystem.

2. The Emergence of HipHop

Facebook recognized the need for optimizing PHP’s performance to meet its scale and demands. To address this, they developed a game-changing solution in the form of HipHop for PHP (HPHP). HPHP is an alternative version of PHP that serves as a compiler, converting PHP code into highly efficient C++ code. This transformation significantly enhances performance and allows Facebook to utilize PHP more effectively in their infrastructure.

3. Introducing HHVM and Hack

In addition to HPHP, Facebook introduced the HipHop Virtual Machine (HHVM). HHVM is a just-in-time compiler for PHP, further improving its execution speed. Alongside HHVM, Facebook also unveiled Hack, a new programming language that builds upon PHP’s syntax while introducing static typing, generics, and native collections. Hack runs exclusively on the HHVM, offering developers a more robust and error-resistant environment.

4. Overcoming PHP’s Limitations

One of the key challenges Facebook faced with PHP was its inability to perform optimally at their massive scale. Type-related errors often remained undetected until runtime, leading to time-consuming debugging processes. To address this, Facebook implemented strict typing and runtime enforcement of return types in Hack. This proactive approach significantly reduces the need for extensive type-related testing and helps catch errors during development.

5. The Coexistence of Zend and HHVM

Despite the remarkable enhancements brought by HHVM and Hack, Facebook continues to coexist with traditional PHP, powered by the Zend Engine. Both engines offer distinct advantages, and Facebook leverages the strengths of each to create a robust and flexible technology stack. This coexistence ensures that Facebook can continually innovate while maintaining stability in its operations.

Conclusion

In conclusion, Facebook’s technology stack is a testament to the company’s commitment to innovation and performance optimization. PHP, HPHP, HHVM, and Hack all play pivotal roles in shaping the tech giant’s infrastructure. By developing alternative versions of PHP and introducing advanced features, Facebook has not only overcome limitations but has also set new standards for efficiency and reliability. The coexistence of Zend and HHVM demonstrates Facebook’s dedication to fostering healthy competition and continually pushing the boundaries of technology within its organization.