JSON in PHP — json_decode, json_encode & Error Handling

PHP has built-in JSON support via json_encode() and json_decode(). No extensions or packages are required.

Parse JSON with json_decode()

json_decode() returns a stdClass object by default. Pass true as the second argument to get an associative array instead.

<?php
$json = '{"name":"Alice","age":30,"active":true}';

// As object (default)
$obj = json_decode($json);
echo $obj->name; // Alice

// As associative array
$arr = json_decode($json, true);
echo $arr['name']; // Alice

Encode to JSON with json_encode()

json_encode() converts a PHP value to a JSON string. Use JSON_PRETTY_PRINT for readable output.

<?php
$data = ['name' => 'Alice', 'age' => 30, 'active' => true];

$json = json_encode($data);
// {"name":"Alice","age":30,"active":true}

$pretty = json_encode($data, JSON_PRETTY_PRINT);
echo $pretty;

Handle encoding and decoding errors

Check json_last_error() after calling json_encode() or json_decode().

<?php
$result = json_decode('invalid json', true);

if (json_last_error() !== JSON_ERROR_NONE) {
    echo 'JSON error: ' . json_last_error_msg();
    // JSON error: Syntax error
}

JSON API response

A standard pattern for returning JSON from a PHP endpoint.

<?php
header('Content-Type: application/json');

$response = ['status' => 'ok', 'data' => ['id' => 1, 'name' => 'Alice']];
echo json_encode($response);

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Frequently Asked Questions

How do I parse JSON in PHP?▾

Use json_decode($json, true) to get an associative array, or json_decode($json) to get a stdClass object. Check json_last_error() to detect failures.

What does the second argument to json_decode() do?▾

Passing true returns an associative array. The default (false/null) returns a stdClass object. For most use cases, true is easier to work with.

How do I pretty-print JSON in PHP?▾

Pass the JSON_PRETTY_PRINT flag to json_encode(): json_encode($data, JSON_PRETTY_PRINT). Combine flags with |: JSON_PRETTY_PRINT | JSON_UNESCAPED_UNICODE.

How do I handle Unicode in PHP JSON encoding?▾

By default, json_encode() escapes non-ASCII characters. Add JSON_UNESCAPED_UNICODE to preserve them: json_encode($data, JSON_UNESCAPED_UNICODE).

How do I check for JSON errors in PHP?▾

Call json_last_error() after json_encode() or json_decode(). Compare the return value to JSON_ERROR_NONE. Use json_last_error_msg() for a human-readable message.

JSON in Other Languages

JSON in Python →JSON in JavaScript →JSON in TypeScript →JSON in Go →JSON in Java →JSON in Ruby →JSON in C# →JSON in Rust →JSON in Kotlin →JSON in Swift →JSON in Dart →JSON in Scala →JSON in Next.js →JSON in Express →JSON in FastAPI →JSON in Django →JSON in Terraform →

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