JSON validator & beautifier

Check that your JSON is valid and make it readable

JSON (JavaScript Object Notation) is the format most APIs, config files and web apps use to exchange data. It's strict: one missing comma, a trailing comma, single quotes or an unquoted key, and the whole document fails to parse. This tool checks your JSON and tells you whether it's valid, then reformats it with consistent indentation so you can actually read it.

Minified JSON from an API response is often a single line thousands of characters long. Beautifying it puts each key on its own line and indents nested objects and arrays, which makes it easy to scan the structure, spot the field you need and compare two responses.

It's useful whether you're debugging a webhook payload, editing a package.json or composer.json, checking data before importing it, or learning how a third-party API structures its responses.

How to use the json validator & beautifier

1. Paste your JSON into the input box.
2. Submit it to validate and format.
3. If the JSON is valid, you'll see a confirmation and a neatly indented version you can copy.
4. If it isn't valid, look for the usual culprits listed below, fix them, and run it again.

Common uses

• Reading minified API responses while debugging an integration.
• Checking a config file for syntax errors before deploying.
• Validating JSON you wrote by hand, such as structured data or test fixtures.
• Making JSON easy to review in a code review or support ticket.
• Inspecting webhook payloads from services like Stripe, GitHub or Slack.

Tips and things to know

• Keys and string values must use double quotes. Single quotes are valid in JavaScript but not in JSON.
• Trailing commas after the last item in an object or array are not allowed.
• JSON has no comments. Remove // or /* */ comments before validating.
• Allowed values are strings, numbers, objects, arrays, true, false and null. undefined, NaN and functions are not valid JSON.
• Avoid pasting production secrets such as API keys or tokens into any online tool. Replace them with placeholders first.
• Working with JSON inside a URL or encoded string? Decode it first with the URL decoder or Base64 decoder.

Frequently asked questions

Why is my JSON invalid?

The most common reasons are a missing or extra comma, single quotes instead of double quotes, unquoted keys, a trailing comma, comments, or a missing closing bracket or brace.

What is the difference between beautifying and minifying JSON?

Beautifying adds line breaks and indentation for humans to read. Minifying removes all unnecessary whitespace to make the data as small as possible for transfer. Both contain exactly the same data.

Is JSON the same as a JavaScript object?

They look similar, but JSON is a stricter text format. It requires double-quoted keys and strings and doesn't allow functions, comments or trailing commas.

Can JSON contain arrays at the top level?

Yes. A JSON document can be an object, an array, or even a single string, number, boolean or null.

Does formatting change my data?

No. Formatting only changes whitespace. Keys, values and their order stay the same.

Related tools

• SQL formatter/beautifier: Format & beautify your SQL code with ease.
• JS minifier: Minify your JS by removing all the unnecessary characters.
• Base64 decoder: Decode Base64 input to back to string.
• URL parser: Parse details from any URLs.
• HTML minifier: Minify your HTML by removing all the unnecessary characters.