Codeigniter 4 REST API Tutorial With Example

In this tutorial, we will learn how to create Codeigniter 4 rest API tutorial, you will learn how to create rest API in PHP Codeigniter 4 frameworks.

If you want to exchange data between apps and servers. So that time, you need to rest APIs for exchange data between servers and apps. we will use CodeIgniter 4 Rest API.

So this Codeigniter 4 rest API tutorial will help you to how to create rest API in Codeigniter 4 framework. And how to create, read, update, and delete data from database table using these APIs.

Before you create a rest API and use it in Codeigniter. You can see the architecture of the RESTful API:

[Codeigniter 4] REST API Tutorial With Example - Step By Step

Codeigniter 4 Rest API From Scratch

Introduction to PHP | How it works ...
Introduction to PHP | How it works | Overview of PHP

In this tutorial, we will learn how to create REST APIs from the very beginning in very easy ways.

Step 1: Create Database And Table

First of all, start your local server and start PHPMyAdmin.

Then use the following command to create a database:


After that, select your database and run the following SQL query to create a Product table into your database:

product_name VARCHAR(200),
product_price DOUBLE

Next, run the following query to insert some data into the product table:

INSERT INTO product(product_name,product_price) VALUES
('Product 1','2000'),
('Product 2','5000'),
('Product 3','4000'),
('Product 4','6000'),
('Product 5','7000');
Step 2: Download Codeigniter Project

In this step, we will download the latest version of Codeigniter 4, Go to this link Download Codeigniter 4 fresh new setup and unzip the setup in your local system xampp/htdocs/ . And change the download folder name “demo”.

Step 3: Basic Configurations

Next, we will set some basic configuration on the app/config/app.php file, so let’s go to application/config/config.php and open this file on the text editor.

Set Base URL like this

public $baseURL = 'http://localhost:8080';
public $baseURL = 'http://localhost/demo/';
Step 4: Setup Database Credentials

In this step, we need to connect our project to the database. we need to go app/Config/Database.php and open database.php file in text editor. After opening the file in a text editor, We need to set up database credentials in this file like below.

public $default = [
    'DSN'      => '',
    'hostname' => 'localhost',
    'username' => 'root',
    'password' => '',
    'database' => 'demo',
    'DBDriver' => 'MySQLi',
    'DBPrefix' => '',
    'pConnect' => false,
    'DBDebug'  => (ENVIRONMENT !== 'production'),
    'cacheOn'  => false,
    'cacheDir' => '',
    'charset'  => 'utf8',
    'DBCollat' => 'utf8_general_ci',
    'swapPre'  => '',
    'encrypt'  => false,
    'compress' => false,
    'strictOn' => false,
    'failover' => [],
    'port'     => 3306,
Step 5: Create Model

So go to app/Models/ and create here one model. And you need to create one model name ProductModel.php and update the following code into your ProductModel.php file:

<?php namespace App\Models;
use CodeIgniter\Model;
class ProductModel extends Model
    protected $table = 'product';
    protected $primaryKey = 'product_id';
    protected $allowedFields = ['product_name','product_price'];
Step 6: Create Controller

Now, Navigate app/Controllers and create a controller name Products.php. Then update the following method into Products.php controller file:

<?php namespace App\Controllers;
use CodeIgniter\RESTful\ResourceController;
use CodeIgniter\API\ResponseTrait;
use App\Models\ProductModel;
class Products extends ResourceController
    use ResponseTrait;
    // get all product
    public function index()
        $model = new ProductModel();
        $data = $model->findAll();
        return $this->respond($data);
    // get single product
    public function show($id = null)
        $model = new ProductModel();
        $data = $model->getWhere(['product_id' => $id])->getResult();
            return $this->respond($data);
            return $this->failNotFound('No Data Found with id '.$id);
    // create a product
    public function create()
        $model = new ProductModel();
        $data = [
            'product_name' => $this->request->getVar('product_name'),
            'product_price' => $this->request->getVar('product_price')
        $response = [
            'status'   => 201,
            'error'    => null,
            'messages' => [
                'success' => 'Data Saved'
        return $this->respondCreated($response);
    // update product
    public function update($id = null)
        $model = new ProductModel();
        $input = $this->request->getRawInput();
        $data = [
            'product_name' => $input['product_name'],
            'product_price' => $input['product_price']
        $model->update($id, $data);
        $response = [
            'status'   => 200,
            'error'    => null,
            'messages' => [
                'success' => 'Data Updated'
        return $this->respond($response);
    // delete product
    public function delete($id = null)
        $model = new ProductModel();
        $data = $model->find($id);
            $response = [
                'status'   => 200,
                'error'    => null,
                'messages' => [
                    'success' => 'Data Deleted'
            return $this->respondDeleted($response);
            return $this->failNotFound('No Data Found with id '.$id);

In the above controller method works as follow:

->Index() – This is used to fetch all products.

->create() – This method is used to insert product info into DB table.

->update() – This is used to validate the form data server-side and update it into the MySQL database.

->show() – This method is used to fetch single product info into DB table.

->delete() – This method is used to delete data from the MySQL database.

Now Navigate to App/Configuration folder. And Open the file “Routes.php”, then find the following code:

$Route->get('/', 'home :: index');

Then, change the following:


This configuration allows us to access the following EndPoint:

Step 7: Start Development Server

Open your terminal and run the following command to start the development server:

php spark serve

I hope it can help you...

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