Flask vs CodeIgniter

Flask is very easy to get up and going, with vanilla HTML or with bootstrap pieces. It doesn't take much lines of Python to load Flask to get headers working, etc, and since it's all modular you don't have to have something you don't want in your application.

Flask is one of the most popular Python web frameworks, if not the most popular one. As such, there's plenty of guides, tutorials, and libraries available for it. A large number of important Python libraries, such as SQLAlchemy have libraries for Flask, which add valuable bindings to make the development process and the integration between these libraries and Flask as easy as possible.

Even though it's pretty minimalistic out of the box, Flask still provides the necessary tools to build a quick prototype for a web app right after a fresh install. With all the main components pretty much packed in the flask package, building a simple web app in a single Python file is as easy as it gets.

Flask gives developers a lot of flexibility in how they develop their web applications.

For example, the choice of not having an ORM, but instead choosing one suited to the task, or another area where Flask gives a lot of options to developers is the templating. They can use Jinja2, Flask's default templating language or choose from a number of different templating languages they desire.

The official documentation is very thorough and complete. Everything is explained in-depth and followed by extremely well-explained tutorials that tackle real-world problems.

Setting up CodeIgniter is quick and easy. You can download the version you want from the CI homepage or directly pull the latest version from GitHub. After that, you unzip the contents to the directory that's required. The final step is to edit the config.php to suit your needs and it's set up and ready for development.

There are also a lot of guides and tutorials from developers who have been using CI for a long time. This is because of the relative old age of the framework and the large community behind it.

CodeIgniter has a small footprint, just 3MB and that's including the user guide.

The documentation is clear, structured and thorough. It explains both commonly used and CodeIgniter specific concepts and always with clear examples.

Because it's relatively old and well-liked, it has an active community of developers behind it. It's used by a lot of websites in production.

The MIT License (MIT)

CodeIgniter is open source and is distributed under the MIT license.

CodeIgniter is tested by hundreds of thousand of developers that use it in production. This means that it's very hard for any bugs or problems to go unnoticed. Even when a new version is out, bugs are quickly found and patched up.

CodeIgniter has it's own templating engine built-in. It's based on a mustache-like templating language which is easy to learn for new developers who have never seen it. While experienced developers will feel very comfortable using it.

CodeIgniter lets you cache the web pages in order to decrease loading times and increase efficiency and performance.

CI4 will be out soon & is a rewrite..
"CodeIgniter 4 is a rewrite of the framework and is not backwards compatible."
So it will support ALOT more newer functionality built-in.