PHP Tutorial · PHP for the Web · Lesson 25 of 38

PHP JSON

Encode arrays and objects as JSON and decode JSON into PHP.

json_encode

Turns arrays and objects into a JSON string. Use flags for readable output:

Example 1Try it yourself

<?php
$data = ["name" => "Ada", "skills" => ["php", "sql"], "active" => true, "score" => null];
echo json_encode($data), "\n";
echo json_encode(["path" => "/api/users", "city" => "Zürich"], JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE), "\n";
echo json_encode([1, 2]), " vs ", json_encode([1 => "a", 2 => "b"]), "\n";
echo json_encode(["id" => 1, "tags" => ["a"]], JSON_PRETTY_PRINT), "\n";

Output

{"name":"Ada","skills":["php","sql"],"active":true,"score":null}
{"path":"/api/users","city":"Zürich"}
[1,2] vs {"1":"a","2":"b"}
{
    "id": 1,
    "tags": [
        "a"
    ]
}

json_decode

Pass true as the second argument to get associative arrays (otherwise you get stdClass objects). Use JSON_THROW_ON_ERROR so invalid JSON throws instead of silently returning null:

Example 2Try it yourself

<?php
$json = '{"id": 7, "title": "Learn PHP", "tags": ["php", "web"]}';
$todo = json_decode($json, true);
echo $todo["title"], " #", $todo["tags"][0], "\n";
$obj = json_decode($json);
echo $obj->title, "\n";
try {
    json_decode("{bad json}", true, flags: JSON_THROW_ON_ERROR);
} catch (JsonException $e) {
    echo "Invalid JSON: ", $e->getMessage(), "\n";
}

Output

Learn PHP #php
Learn PHP
Invalid JSON: Syntax error

A JSON API endpoint

<?php
header("Content-Type: application/json");
echo json_encode(["status" => "ok", "items" => $items]);

Test yourself

What second argument makes json_decode() return arrays instead of objects?

true
false
JSON_ARRAY
1.0

Show answer

Answer: true