PHP is one of the most prominently used open-source languages. It's executed on the server and is free for all forms of usage, making it a cost-effective solution for any web development process.

PHP is generally used for its wide range of benefits. It can generate dynamic content, manipulate server files, aggregate data, manage cookies, execute several other functions and is compatible with Windows, Linux, and Mac OS X. It can work with practically every essential server like Apache, IIS, and others.

Moreover, its prominence can be gauged from the fact that websites as vast and varied a WordPress and Facebook use PHP in their tech-stack. While PHP itself is a powerful scripting language, PHP web frameworks make it all the more powerful. Symfony and CodeIgniter are two of the most popular frameworks in this cohort.

Symfony

Symfony is one of the best web frameworks and is ideal for websites as well as web applications. It comes with a series of over 50 components that are decoupled and reusable. Put together, the Symfony PHP Framework and the components provide a powerful suite of tools that have been used to develop & deploy products like Drupal and phpBB.
The framework boasts a community of nearly 600,000 developers and 3,000 contributors spread across 120 countries.

Pros

Most professional developers who use Symfony recommend that it is a great framework for enterprise web development. This is because of its reusable components that exponentially expedite the development lifecycle.
Moreover, most observers of the Symfony community state that the size & scale of the contributors make it an actively engaging community. It is not difficult to find standard operating procedures, best practices, and answers to common queries on the Symfony community website.

The framework has been used to develop several open-source Content Management Platforms like Drupal, phpBB, and even OroCRM. This shows that it can be actively used as a stable and reliable framework. Symfony works seamlessly with autoloaders and composers. For larger development teams, this can lead to resource optimization.

Cons

With an open-source concept, an active community, and some stable products developed using the framework at the display – it would be hard to locate cons with the framework. If you are a beginner-level developer, there is a high chance that you will find it tough to work with Symfony. This also limits the accessibility of the framework for large companies that are frequently hiring new talent.

CodeIgniter

CodeIgniter is one of the oldest backend web frameworks. Right when PHP became mainstream, the framework started getting traction among developers. It is known for its lightweight application, straightforward documentation, and ease of use.

Pros

If you are looking for a lightweight PHP framework that does not compromise your desired configuration – CodeIgniter will fit the bill. You can get started by downloading CodeIgniter 4.0, which occupies just 1.2 MB of space.

The framework does not require a comprehensive configuration. You can use it from the get-go with minor changes as necessary. It does not force the MVC (Model, View, and Control) framework. But, the Control aspects are mandatory.
CodeIgniter is also known for its relatively faster database operations. It does not require parsers. Both these features put together result in smoothly running web applications that do not require PHP code conversions. Moreover, it does not make it mandatory for developers to stick to a template engine for backend code integration. This makes the backend web development process easier to execute.

Cons

CodeIgniter is a viable option as a lightweight framework. However, it has its drawbacks. First and foremost are the missing debugging tools.
Most popular PHP frameworks like Laravel and Symfony have native debugging capabilities or some inherent tools that make it easy to debug the codebase. Since these are not readily available, programmers have to debug the code manually.

Another drawback is the ORM tool integration method. Unlike other frameworks, ORM tools have to be installed as plug-ins. This can lead to more time spent on integration or an unstable tech stack if not done carefully.
Relative to Symfony, CodeIgniter does not have the capability of auto-generating modules & databases. This increases the need for writing code.

How to Choose Between Symfony and CodeIgniter?

Performance: The average response time for CodeIgniter is non-linear. A test shows an application with 100 users had an average response time of approximately 11.5 seconds, but an application with 1100 users had the same metric measured at 26 seconds.
On the other hand, Symfony is known to be slower than Laravel – which is a comparable framework for understanding performance at scale. This makes CodeIgniter a preferable framework if performance is the only metric.

Security:

CodeIgniter does not have several rudimentary features like controller security. Symfony, being a newer PHP framework, is a preferable alternative.
Besides that, it must be noted that both frameworks have open source licensing. Hence, there is not much available in native format for any of the two frameworks in terms of security. Symfony has the edge over CodeIgniter simply because the latter misses a few critical and essential features.

Learning Curve:

Learning Curve indicates the difficulty of learning the next most critical skill under the umbrella of a concept. This would mean that if your team does not have any of the two PHP frameworks included in its tech stack, how much time would it take for your team to understand each of the two alternatives?

CodeIgniter comes with easy-to-understand documentation, does not require complex configuration, and is known as a lightweight framework. Symfony, being a more complex framework, has a steeper learning curve.

Community:

Theoretically, CodeIgniter should have had a more extensive community since it is an older framework. However, Symfony has a community of over 3,000 active contributors and 600,000 members across the globe. The same trend is visible on the GitHub pages for both the frameworks – Symfony and CodeIgniter.

Debugging Abilities:

CodeIgniter has not native debugging capabilities. Symfony has a debugging toolbar that supports efficient debugging.

Which Brands Use Symfony?

Several leading brands like Spotify, Trivago, Dailymotion, and Course Hero use Symfony. Interestingly, even Laravel was developed using Symfony. Some other prominent users of Symfony are Vogue France, Nat Geo Play France, the Swiss Government's Open Data platform, and European Space Software Repository.

As visible, Symfony’s capabilities to support synchronization across several devices and interface-level translation make it the apt framework for platforms similar to those listed here.

Why Brands Use CodeIgniter?

Most active developer communities have already declared CodeIgniter to be an outdated tool. However, in the hands of professionals who can use plug-ins to cover the shortcomings of CodeIgniter, it can be a powerful contributor to the tech stack. Companies like Accenture, Ola, and Buffer use CodeIgniter. These are companies that often have an extensive suite of products used by millions of users at a time. Using CodeIgniter provides them with the needed agility and freedom of configuration as they see fit.

In Conclusion

In terms of backend web frameworks, both CodeIgniter and Symfony have their utility. Symfony comes loaded with features and is considered quite comprehensive. However, this also makes it marginally slower in its response time. It is also considered complex for beginner-level developers.
CodeIgniter, on the other side, is perceived to be one of the older PHP frameworks. That said, several leading technology companies are still using the framework.

So, how do you choose between the two? If you seek native features, have a team of experienced developers, and want a framework suited for enterprise-grade websites and web applications – Symfony is the alternative you should opt for.
If you are seeking a lightweight framework that gives your team ample freedom in terms of execution and integration and is easy to use even for the new members of your team – CodeIgniter will work well for you.