JSON Formatter

Format and validate JSON data. Beautify or minify JSON strings.

Input Text:

0 characters

Output:

What is a JSON Formatter?

A JSON formatter is a tool that takes messy, unformatted JSON data and converts it into a clean, readable format with proper indentation and line breaks. It also validates that your JSON is syntactically correct.

Essential Uses of JSON Formatting

Debugging API Responses: When calling REST APIs, responses are often minified (no whitespace, single line). Formatting these responses makes them readable for debugging. For example, a minified API response {"user":{"id":123,"name":"John","roles":["admin","editor"]}} is hard to parse visually. Formatted with indentation, the structure becomes clear. You can see the nested user object, the id and name fields, and the roles array. Essential for verifying API behavior, inspecting nested data, and debugging integration issues.
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Analyzing Log Files and Error Messages: Application logs, error messages, and monitoring systems often output JSON. These JSON blobs are typically minified and difficult to read. Formatting log JSON helps you understand error context, trace nested data structures in logs, and analyze application behavior. For example, formatting a structured log entry reveals the timestamp, log level, message, and contextual data clearly.
Editing Configuration Files: Modern applications use JSON for config files: package.json (Node.js), composer.json (PHP), tsconfig.json (TypeScript), launch.json (VS Code), etc. When these files are minified or poorly formatted, editing them becomes error-prone. Formatting ensures proper indentation, making it easy to spot syntax errors (missing commas, unclosed brackets) and understand configuration structure. Always format before editing, and validate after.

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JSON: The Universal Data Format

JSON was created by Douglas Crockford in the early 2000s as a lightweight alternative to XML for data interchange. Derived from JavaScript object literal syntax, JSON quickly became the de facto standard for web APIs due to its simplicity and readability. RFC 8259 formally standardized JSON in 2017. Today, JSON is used by virtually every REST API (GitHub, Twitter, Google, etc.), NoSQL databases (MongoDB, CouchDB), configuration files (package.json, tsconfig.json), and data pipelines. Its human-readable syntax makes formatting essential. Developers need to read and understand JSON during development, but minification is crucial for production bandwidth optimization.

JSON Security Considerations

JSON formatting does not validate data safety. Always validate and sanitize JSON content from untrusted sources before using it in your application. Learn about encoding security

JSON Formatting in Programming Languages

Every programming language can format (beautify) and minify JSON. Here are comprehensive examples:

// Beautify (pretty print)
$formatted = json_encode($data, JSON_PRETTY_PRINT | JSON_UNESCAPED_SLASHES);
// Result: formatted with 4-space indent

// Minify (compact)
$minified = json_encode($data);
// Result: no whitespace

// With custom options
$json = json_encode($data,
    JSON_PRETTY_PRINT |
    JSON_UNESCAPED_UNICODE |
    JSON_UNESCAPED_SLASHES
);

// Parsing (with error handling)
$data = json_decode($jsonString, true);
if (json_last_error() !== JSON_ERROR_NONE) {
    echo "JSON Error: " . json_last_error_msg();
}

// Beautify with 2-space indent
const formatted = JSON.stringify(data, null, 2);

// Beautify with 4-space indent
const formatted = JSON.stringify(data, null, 4);

// Minify (compact)
const minified = JSON.stringify(data);

// Parse with error handling
try {
    const data = JSON.parse(jsonString);
} catch (error) {
    console.error("JSON parse error:", error.message);
}

// Replacer function (custom serialization)
const json = JSON.stringify(data, (key, value) => {
    // Exclude private fields
    if (key.startsWith('_')) return undefined;
    return value;
}, 2);

import json

# Beautify with 2-space indent
formatted = json.dumps(data, indent=2)

# Beautify with sorted keys
formatted = json.dumps(data, indent=2, sort_keys=True)

# Minify (compact)
minified = json.dumps(data, separators=(',', ':'))
# separators removes spaces after commas and colons

# Parse with error handling
try:
    data = json.loads(json_string)
except json.JSONDecodeError as e:
    print(f"JSON error: {e.msg} at line {e.lineno}")

# Pretty print to console
print(json.dumps(data, indent=2))

import (
    "encoding/json"
    "fmt"
)

// Beautify with indent
formatted, err := json.MarshalIndent(data, "", "  ")
if err != nil {
    fmt.Println("JSON marshal error:", err)
}

// Minify (compact)
minified, err := json.Marshal(data)

// Parse with error handling
var data MyStruct
err := json.Unmarshal([]byte(jsonString), &data)
if err != nil {
    fmt.Println("JSON unmarshal error:", err)
}

// Custom indentation
formatted, _ := json.MarshalIndent(data, ">", "----")
// Prefix: >, indent: ----

import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import com.google.gson.JsonSyntaxException;

// Beautify
Gson gson = new GsonBuilder()
    .setPrettyPrinting()
    .create();
String formatted = gson.toJson(data);

// Minify
Gson gson = new Gson();
String minified = gson.toJson(data);

// Parse with error handling
try {
    MyObject obj = gson.fromJson(jsonString, MyObject.class);
} catch (JsonSyntaxException e) {
    System.err.println("JSON error: " + e.getMessage());
}

require 'json'

# Beautify
formatted = JSON.pretty_generate(data)
# Default: 2-space indent

# Beautify with custom indent
formatted = JSON.pretty_generate(data, indent: '    ')
# 4-space indent

# Minify
minified = JSON.generate(data)

# Parse with error handling
begin
  data = JSON.parse(json_string)
rescue JSON::ParserError => e
  puts "JSON error: #{e.message}"
end

using Newtonsoft.Json;

// Beautify (pretty print)
string formatted = JsonConvert.SerializeObject(data,
    Formatting.Indented);

// Minify (compact)
string minified = JsonConvert.SerializeObject(data,
    Formatting.None);

// Parse with error handling
try
{
    var obj = JsonConvert.DeserializeObject<MyObject>(jsonString);
}
catch (JsonException ex)
{
    Console.WriteLine($"JSON error: {ex.Message}");
}

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