PHP JSON Response

A JSON response is data returned by the server in JSON format after an API request is processed.

{
    "success": true,
    "message": "Student created successfully"
}

The client can read this response and decide what to display to the user.

JSON is easy for mobile applications and web applications to process.

React Native
      ↓
HTTP Request
      ↓
PHP REST API
      ↓
JSON Response
      ↓
React Native

A consistent JSON structure makes API integration easier.

The API should tell the client that the response contains JSON.

header("Content-Type: application/json");

This header should normally be sent before outputting the JSON response.

PHP arrays can be converted into JSON using json_encode().

$response = [
    "success" => true,
    "message" => "API is working"
];

echo json_encode($response);

A successful operation can return a response such as:

{
    "success": true,
    "message": "Student created successfully"
}

The success property tells the client that the operation was successful.

An API can return a JSON response when something goes wrong.

{
    "success": false,
    "message": "Student not found"
}

The client can display the message or perform another action.

An API response contains both an HTTP status code and a response body.

HTTP Status
     +
JSON Body

The status code provides a standard indication of the result of the HTTP request.

PHP provides http_response_code() to set the HTTP status code.

http_response_code(200);

This sets the response status to 200.

HTTP 200 is commonly used when a request has been successfully processed.

http_response_code(200);

echo json_encode([
    "success" => true,
    "message" => "Student fetched successfully"
]);

HTTP 201 is commonly used when a new resource has been created.

http_response_code(201);

echo json_encode([
    "success" => true,
    "message" => "Student created successfully"
]);

This is useful for a successful POST operation that creates a new student.

These status codes help the client understand why a request failed.

HTTP 400 can be used when the client sends invalid data.

http_response_code(400);

echo json_encode([
    "success" => false,
    "message" => "Invalid student data"
]);

HTTP 404 can be used when the requested resource does not exist.

http_response_code(404);

echo json_encode([
    "success" => false,
    "message" => "Student not found"
]);

HTTP 500 is commonly used when the server encounters an unexpected error.

http_response_code(500);

echo json_encode([
    "success" => false,
    "message" => "Internal server error"
]);

A JSON response can contain actual API data.

$student = [
    "id" => 1,
    "name" => "Rahul",
    "email" => "rahul@example.com"
];

echo json_encode([
    "success" => true,
    "data" => $student
]);

A response can also contain multiple records.

$students = [
    [
        "id" => 1,
        "name" => "Rahul"
    ],
    [
        "id" => 2,
        "name" => "Amit"
    ]
];

echo json_encode([
    "success" => true,
    "data" => $students
]);

For a list response, the total number of records can also be returned.

echo json_encode([
    "success" => true,
    "total" => count($students),
    "data" => $students
]);

This can be useful when displaying lists and pagination information.

A useful error response can contain a clear message.

echo json_encode([
    "success" => false,
    "message" => "Email is required"
]);

Avoid exposing sensitive server or database information in responses sent to clients.

Using a consistent response structure makes the API easier to consume.

Success:

{
    "success": true,
    "message": "...",
    "data": {}
}

Error:

{
    "success": false,
    "message": "..."
}

A reusable function can reduce repeated response code.

function sendResponse(
    int $status,
    array $data
) {

    http_response_code($status);

    echo json_encode($data);

    exit;
}

Now different API operations can use the same function.

sendResponse(200, [
    "success" => true,
    "message" => "Student fetched successfully",
    "data" => $student
]);

The function sets the status code, converts the array to JSON, outputs the response, and stops execution.

sendResponse(404, [
    "success" => false,
    "message" => "Student not found"
]);

The same function can be used for both successful and error responses.

<?php

header("Content-Type: application/json");

function sendResponse(
    int $status,
    array $data
) {

    http_response_code($status);

    echo json_encode($data);

    exit;
}

sendResponse(200, [
    "success" => true,
    "message" => "API is working"
]);

?>

$student = [
    "id" => 1,
    "name" => "Rahul",
    "course" => "PHP"
];

sendResponse(200, [
    "success" => true,
    "message" => "Student fetched successfully",
    "data" => $student
]);

if ($name === '') {

    sendResponse(400, [
        "success" => false,
        "message" => "Name is required"
    ]);
}

This keeps validation response code short and consistent.

React Native can convert the API response into JavaScript data.

fetch(url)
    .then(response => response.json())
    .then(data => {

        console.log(data);

        if (data.success) {
            console.log(data.message);
        }

    });

The application can use the success property to decide what to do next.

PHP Operation
      ↓
Determine Result
      ↓
HTTP Status Code
      ↓
PHP Array
      ↓
json_encode()
      ↓
JSON Response
      ↓
React Native

• Always return JSON from JSON API endpoints.
• Set the Content-Type correctly.
• Use meaningful HTTP status codes.
• Keep response structures consistent.
• Return clear success and error messages.
• Include data only when appropriate.
• Do not expose passwords or sensitive information.
• Do not expose internal database errors to clients.

A professional REST API should return a clear JSON response together with an appropriate HTTP status code. PHP can use http_response_code() to set the status and json_encode() to create the JSON response.

API Operation
     ↓
HTTP Status
     ↓
PHP Array
     ↓
json_encode()
     ↓
JSON Response
     ↓
React Native