REST API stands for REpresentational State Transfer Application Programming Interface. It uses standard HTTP methods like GET, POST, PUT, PATCH, and DELETE to perform database operations on resources. It allows different software applications to communicate with each other over the web. REST APIs are stateless, scalable, and follow standard protocols. Different HTTP requests are used to perform different database operations. HTTP request GET is used to list all the records. HTTP request POST is used to create a new record. HTTP request PUT is used to edit an existing record. HTTP request DELETE is used to delete an existing record. We are showing an example to create a new user through REST API. 1. First of all we have to create a database. include 'db.php'; 2. Then we have to check the method of HTTP request. $method = $_SERVER['REQUEST_METHOD']; 3. We need to accept the user input. $input = json_decode(file_get_contents('php://input'), true); 4. We are calling the method that handle the user creation. if ($method == "POST") { handlePost($pdo, $input); } 5. Write the method to perform the task of creating a new user. function handlePost($pdo, $input) { } 6. Write the SQL within the function. function handlePost($pdo, $input) { $sql = "INSERT INTO users (name, email) VALUES (:name, :email)"; } 7. Create the prepare statement. function handlePost($pdo, $input) { $sql = "INSERT INTO users (name, email) VALUES (:name, :email)"; $stmt = $pdo-gt;prepare($sql); } 8. Execute the statement to create a new user. function handlePost($pdo, $input) { $sql = "INSERT INTO users (name, email) VALUES (:name, :email)"; $stmt = $pdo-gt;prepare($sql); $stmt-gt;execute(['name' =gt; $input['name'], 'email' =gt; $input['email']]); } 9. Show the message. function handlePost($pdo, $input) { $sql = "INSERT INTO users (name, email) VALUES (:name, :email)"; $stmt = $pdo-gt;prepare($sql); $stmt-gt;execute(['name' =gt; $input['name'], 'email' =gt; $input['email']]); echo json_encode(['message' =gt; 'User created successfully']); } In this way we can create REST APIs for listing users, edit user details, delete a user record.