Symfony

Symfony is a collection of PHP components, a web application framework, a philosophy, and a community that all work together seamlessly. The premier PHP framework for building webpages and web applications. Built on top of Symfony Components. A collection of modular and reusable components that serve as the foundation for the top PHP applications, including Drupal, phpBB, and eZ Publish. 

A passionate community of over 600,000 developers from more than 120 countries, all dedicated to helping PHP achieve the unthinkable. Embracing and encouraging professionalism, best practices, standardization, and application interoperability.

Six Good Reasons to Use Symfony 

Reputation 
Symfony was quickly accepted by specialists in this industry after its inception in 2005, and it is now a solid environment that is well-known and acknowledged internationally. The quantity of references attests to this, as they have increased dramatically since its inception. The app also has an active community of developers, integrators, users, and other contributors who work together to improve the tool on a regular basis. 

Permanence 
SensioLabs, an interactive agency, first produced it. Symfony is first and foremost a pragmatic tool, with capabilities that address real-world requirements. Permanence also refers to long-term assistance. SensioLabs provides professional web app support, but since the app's introduction, an entire ecosystem has evolved around it: the community (Slack, Stack Overflow, etc.) and the many additional service firms that have invested in the framework. 

References 
Intranets, big public sites, social networks, community websites, management and workflow tools, and so on. There are many of examples. Hundreds of websites and applications of all sizes and sorts rely on the components. This is especially true with Yahoo!, Dailymotion, Opensky.com, Exercise.com, and even apps like phpBB and Drupal. 

Innovation 
The application has all of the features you'd expect from a framework, including speed, flexibility, and reusable components. Then there's the structure of what's been created and the application of best practices. Not bad! But that's not all! SensioLabs has formed a habit of disrupting the existing order and is constantly pushing for perfection, and its entire community has fostered a spirit of curiosity that extends far beyond PHP. Furthermore, in order to boost developer productivity on an ongoing basis, the "web debug toolbar" was envisioned, drawing on other frameworks, whether PHP or not. 

Resources 
When you use Symfony, you never have to worry about "being alone with your screen." You will always find answers to your issues, whether they are about community support (mailing lists, IRC, etc.) or company assistance (consulting, training, etc.). Beginning with the idea that "an undocumented line is a line that does not exist," you will find many works dedicated to the app that will assist you in the construction of your sites and applications. 

Interoperability 
The concept of Symfony is to not lock yourself up within it! Allow yourself to create applications that precisely fit your requirements! The framework adheres to PHP's current "de facto standards" such as PHPUnit and class naming rules, among others. Furthermore, it lets you to use specific software building components (dependency injector, translations management, forms management, and so on) without having to use the complete framework. 

Requires PHP.