Lumen VS CodeIgniter

Official website: lumen.laravel.com

I think there are micro frameworks like lumen that are far more accessible in the first steps (https://lumen.laravel.com).

see also: https://github.com/laravel/lumen

use lumen. it is exactly what you want. https://lumen.laravel.com/

If you're concerned about frameworks perhaps being "overkill" for what you want to do with PHP, you'll be happy to hear that Symfony is a microframework out of the box (all components outside of the core framework are 100% optional), and Laravel also has a microframework variant called Lumen.

I would let a framework handle this for you. It can render your HTML views and handle the security for you. It’s been a while since I’ve coded PHP, but I used to love https://laravel.com and https://lumen.laravel.com

Have a look at Laravel Lumen A micro version of Laravel from Laravel.

Codeigniter - Open Source PHP Framework (originally from EllisLab)

Could you care to elaborate on the "CI3 is dangerously out of date" statement? What exactly makes it dangerous? The last version (3.1.11) was released in 2019, and until version 4.1 a few months ago, CI3 was still the current stable version. According to codeigniter.com, "This version is in maintenance, receiving mostly just security update".

CodeIgniter is a commanding PHP framework. If we consider web applications with advanced features, then to create such an application Code igniter is one of the efficient PHP Frameworks. As it makes web applications always ready, learning becomes easier.

CodeIgniter is a rapid web application development framework with a ridiculously small size. CodeIgniter 4, the latest version of CodeIgniter, is a mere 1.2 MB in size. Like Laravel, it’s open-source and boasts 18k+ stars on GitHub. Just because of how bare-bone it is, we have included it in the second position. Like several other frameworks, CodeIgniter provides a set of libraries and an intuitive interface to accelerate PHP web app development. Currently, this is not tracked by PHPbenchmarks.com but is considered among the best PHP frameworks for website development.

During our interim presentation when the panel asked us "Why do you use MVC?" and asked us to view the content of the default controller and model we did not know the answers and afterwards we soon realized it has something to do with how the framework had been set-up in environments such as CodeIgniter and Laravel

At my day job we needed to develop an API and I've never really tried to build one using vanilla PHP, but instead used frameworks such as CodeIgniter or Slim or just a simple file that would mimic the functionality of an API but not be a proper one. Also we had a requirement that we needed to have full control over the code so we were not supposed to use any of the pre built solutions because of that requirement.