JSON Viewer, Validator & Formatter

Pretty-print, validate, minify and inspect JSON for API responses, configs, logs and webhook payloads.

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About JSON Viewer, Validator & Formatter

This JSON viewer helps you format, validate, minify, and inspect JSON data in real-time. Whether you're debugging API responses, editing configuration files, or analyzing webhook payloads, this tool makes it easy to spot syntax errors and understand nested structures at a glance.

Common JSON Errors This Tool Catches

JSON Syntax Highlighting Colors

The formatted output uses distinct colors for different data types, making it easier to scan large JSON structures:

When to Use This Tool

Developers commonly use this JSON viewer for: debugging REST API responses in development, validating configuration files (package.json, tsconfig.json, etc.), inspecting webhook payloads from services like Stripe or GitHub, formatting minified JSON from logs, and learning JSON syntax when starting with web development.

How to Validate and Format JSON

  1. Paste your JSON: Copy raw JSON from your API response, config file, or log output into the input area above.
  2. Click "Format": The tool will parse your JSON and display it with proper indentation and syntax highlighting.
  3. Review the output: Check for syntax errors (displayed in red) or verify the formatted structure looks correct.
  4. Use additional options: Click "Minify" to compress JSON for transmission, or "Validate" to check syntax without reformatting.
  5. Copy the result: Click "Copy Result" to paste the formatted JSON into your editor or documentation.

Example Input and Output

Input (minified):

{"name":"John","age":30,"city":"New York","hobbies":["coding","reading"]}

Output (formatted):

{
    "name": "John",
    "age": 30,
    "city": "New York",
    "hobbies": ["coding", "reading"]
}

Frequently Asked Questions

What causes 'Invalid JSON' errors when the data looks correct?
Common causes include: trailing commas after the last array/object item (e.g., [1,2,3,]), unquoted keys ({name:"value"} instead of {"name":"value"}), single quotes instead of double quotes, and JavaScript comments. JSON is stricter than JavaScript object literals.
Is my JSON data sent to a server?
No. This JSON viewer runs entirely in your browser using the native JSON.parse() method. Your data never leaves your device, making it safe for sensitive API responses, config files, and production logs.
How do I fix JSON with trailing commas?
Remove the comma after the last item in arrays and objects. For example, change {"a":1,"b":2,} to {"a":1,"b":2}. Many code editors have 'remove trailing commas' features, or paste into this validator to locate the exact error position.
What is the difference between JSON and JavaScript objects?
JSON requires double quotes for all keys and string values, does not allow trailing commas, has no functions or undefined values, and uses null instead of undefined. JavaScript objects are more flexible but cannot be safely parsed by JSON.parse().