This book is for anyone who wants to build their first applications in CodeIgniter 4, this writing offers a step-by-step introduction to the framework, knowing the most relevant aspects of it and is focused above all on practice; It is assumed that the reader has knowledge and has developed in PHP and related technologies of the language, such as JavaScript, HTML and CSS, since, remember that to use any framework, you have to have the bases that support it, that is, your programming language. The book is aimed at those people who want to learn something new, learn about a framework that has very little documentation, who want to improve a skill in web development, who want to grow as a developer and who want to continue scaling their path with other frameworks superior to this one. As long as you meet at least some of the above considerations, this book is for you. Map This book has a total of 21 chapters and consists of explanations and practices. Chapters: Chapter 1: This chapter is intended to explain the environment needed to develop in CodeIgniter 4. Chapter 2: We take the first steps with the frameworks, we will know the official website of the framework. Chapter 3: It is a practice for you, in which you have to create another CRUD. Chapter 4: You will know how to use the routes, grouped routes, their options and the different types. Chapter 5: We will know the use of the session and also of the flash session to save data and present it to the user. Chapter 6: You will learn to manage views in a reusable way. Chapter 7: We will see how to use a more modular scheme when defining controllers for each type of module. Chapter 8: We will know how to work with forms. Chapter 9: We will learn more about models. Chapter 10: We will learn to use filters to intercept requests. Chapter 11: In this chapter we build a Rest Api type CRUD that can be consumed with JSON or XML. Chapter 12: In this chapter you will learn to generate test data with seeders. Chapter 13: In this chapter we will learn how to handle the relational schema of the database in CodeIgniter. Chapter 14: In this chapter we are going to work with uploading files in our application. Chapter 15: This chapter provides an introduction to the use of the libraries and help functions and how to use them. Chapter 16: This chapter we will adapt Bootstrap 5 components in the application. Chapter 17: This chapter we will create an end user module with list and detail page. Chapter 18: This chapter we will make some changes in the Rest Api created previously to define additional methods such as upload, pagination, among others. Chapter 19: App with Vue, coming soon. Chapter 20: In this chapter we will learn how to integrate the PayPal platform in CodeIgniter, in order to process payments directly from the application. Chapter 21: This chapter we will learn how to integrate CodeIgniter shield to handle authentication and authorization. By the end of the book, you will have the knowledge to create any basic application with the framework and know more t
