JSON Formatter / Validator

JSON Formatter and Validator — Readable JSON in One Click

JSON (JavaScript Object Notation) is the most common format for data exchange on the web. Every REST API, most configuration files, and a huge amount of browser storage data is JSON. The problem is that JSON in its raw, compact form — especially API responses — is a single long line with no whitespace, making it effectively unreadable. This tool formats it into properly indented, human-readable structure and also validates the syntax so you know whether it's valid JSON or not.

What does the formatter do?

It takes raw JSON text — whether compact or already partially formatted — and produces a clean version with consistent 2-space indentation, each key-value pair on its own line, and nested objects and arrays indented to show their level in the hierarchy. The result is much easier to read and navigate, especially for deeply nested data.

The validator checks that the JSON is syntactically correct: all strings are in double quotes, keys are quoted, there are no trailing commas, braces and brackets are balanced, and no JavaScript-specific features (like comments or undefined values) are present. If there's an error, it tells you where the problem is so you can fix it.

Common use cases

Reading API responses: You're testing an API with Postman, curl, or a browser dev tools request, and the response comes back as a blob of text with no whitespace. Paste it here to instantly see the structure. This is the most common reason someone reaches for a JSON formatter.

Debugging a JSON configuration file: Many apps are configured with JSON files — package.json for Node.js projects, firebase.json, launch.json in VS Code, tsconfig.json, and countless others. If your config isn't working and you suspect a syntax error, validate it here. The error message will point to the problem line.

Understanding webhook payloads: Payment gateways (Razorpay, PayU, Cashfree) and platform integrations send data to your server as JSON payloads. Format a sample payload to understand what fields it contains before you write the code to process it.

Reviewing stored data: Browser localStorage and sessionStorage values are often stringified JSON. Open DevTools, copy the stored value, and format it here to read what's actually stored.

Working with Indian government APIs: Several government APIs (GSTN, DigiLocker, banking APIs via the Account Aggregator framework) return JSON responses. The official documentation sometimes doesn't show well-formatted examples — paste a real response here to understand the actual structure.

Cleaning up generated JSON: If your code generates JSON dynamically and you're not sure the output is correctly structured, format and validate it here to confirm before sending it to another service.

How to use it

Paste your JSON into the input box. The tool automatically attempts to format it. If the JSON is valid, the formatted version appears in the output. If there's a syntax error, an error message tells you approximately where the problem is. Fix the error in the input, and re-format.

You can also use it in the opposite direction — take formatted JSON and minify it (remove all whitespace) to prepare it for sending in an API request or storing in a compact format.

Common JSON syntax mistakes

Trailing commas: {"name": "Akash",} — the comma after the last property is not valid in JSON (it's fine in JavaScript object literals but JSON is stricter). Remove it.

Single quotes: {'name': 'Akash'} — JSON requires double quotes for all strings and keys. Single quotes are invalid.

Unquoted keys: {name: "Akash"} — in JSON, every key must be a quoted string. This is valid JavaScript object notation but not valid JSON.

Comments: JSON does not support comments. // this is a comment or /* block comment */ inside a JSON file will cause a parse error. If you're working with a config format that supports comments (like JSONC or JSON5), you'll need a different tool.

Undefined values: {"value": undefined} — undefined is a JavaScript keyword, not a JSON value. Use null instead.

Tips

For very large JSON files (several MB), the browser-based formatter may be slower than a desktop tool. But for typical API responses and config files — usually well under a megabyte — it handles the task almost instantly.

If you need to repeatedly format JSON responses during development, consider browser extensions like "JSON Formatter" for Chrome or Firefox — they automatically format any JSON response displayed in the browser. This tool is best for one-off formatting tasks or for validating specific chunks of JSON.

Limitations

This tool handles standard JSON only — it does not support JSONC (JSON with Comments), JSON5, or any other JSON superset. If your input contains comments or other non-standard features, it will be reported as invalid.

There's no JSON path querying or filtering here. If you want to extract a specific nested value from a large JSON structure rather than just reading it, you'll need a tool like jq or a script using Python's json library.