Learn how to create a custom API in Magento 2

To create a custom API in Magento 2, follow these steps:

Create a module by creating a registration.php file in the app/code directory and adding the following code:

<?php
\Magento\Framework\Component\ComponentRegistrar::register(
    \Magento\Framework\Component\ComponentRegistrar::MODULE,
    'Vendor_Module',
    __DIR__
);

Create a module.xml file in the app/code/Vendor/Module/etc directory and add the following code:

<?xml version="1.0"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:Module/etc/module.xsd">
    <module name="Vendor_Module" setup_version="1.0.0">
        <sequence>
            <module name="Magento_Webapi"/>
        </sequence>
    </module>
</config>

Create a webapi.xml file in the app/code/Vendor/Module/etc/webapi_rest directory and add the following code:

<?xml version="1.0"?>
<routes xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:module:Magento_Webapi:etc/webapi_rest.xsd">
    <route url="/V1/custom/hello" method="GET">
        <service class="Vendor\Module\Api\HelloInterface" method="sayHello"/>
        <resources>
            <resource ref="anonymous"/>
        </resources>
    </route>
</routes>

Create the HelloInterface file in the app/code/Vendor/Module/Api directory and add the following code:

<?php

namespace Vendor\Module\Api;

/**
 * Hello API interface.
 */
interface HelloInterface
{
    /**
     * Say hello.
     *
     * @param string $name
     * @return string Greeting message with customer name.
     */
    public function sayHello($name);
}

Create the Hello file in the app/code/Vendor/Module/Model/Hello directory and add the following code:

<?php

namespace Vendor\Module\Model\Hello;

use Vendor\Module\Api\HelloInterface;

/**
 * Hello model.
 */
class Hello implements HelloInterface
{
    /**
     * Say hello.
     *
     * @param string $name
     * @return string Greeting message with customer name.
     */
    public function sayHello($name)
    {
        return "Hello, $name!";
    }
}

Run the following command to enable the module:

php bin/magento module:enable Vendor_Module
php bin/magento setup:upgrade
php bin/magento setup:di:compile

… and that’s it! Your custom API is now accessible on https://www.example.com/V1/custom/hello