JSON Formatter

Make messy JSON readable in one click

You just grabbed an API response and it’s a 2000-character single line. Or you’re staring at a package.json someone edited without formatting. Paste the blob here, pick your indentation (2 spaces, 4 spaces, or tabs), and get clean, indented JSON back instantly.

The tool validates while it formats, if there’s a syntax error, you’ll see exactly what went wrong and roughly where. Trailing commas, missing quotes, mismatched brackets, it catches the usual suspects.

The thing about unformatted JSON

{"name":"John","age":30,"address":{"street":"123 Main St","city":"New York"}} tells you basically nothing at a glance. Formatted:

{
  "name": "John",
  "age": 30,
  "address": {
    "street": "123 Main St",
    "city": "New York"
  }
}

Now you can see the structure. You can spot the missing field. You can compare it to another response. Formatting isn’t about making things pretty, it’s about making JSON debuggable.

Where this saves time

API debugging: you’re in the network tab, the response is minified, and you need to find a specific nested field. Format it and the hierarchy is obvious.

Config file cleanup: someone committed a messy tsconfig.json. Format it before the code review so the diff shows actual changes, not whitespace.

Data comparison: formatting two JSON objects with the same indentation makes visual diffing possible (or use the JSON Diff Checker for structural comparison).

Documentation: well-formatted JSON examples are non-negotiable for good API docs.

Quick tips

Stick with 2 spaces for JS/TS projects and 4 spaces for Python/Java. Match your project’s conventions.

Format before committing to Git. Clean diffs, easier reviews, less noise.

Everything runs client-side in your browser. Safe for API keys, tokens, whatever sensitive data you’re inspecting.

FAQ

What if my JSON is invalid?

You’ll get an error message showing what went wrong and approximately where. Fix the issue and try again, or use the JSON Validator for detailed diagnostics.

Can it handle big files?

Yes, no upload limits since it’s all in-browser. Files over 10MB might take a moment depending on your device.

Formatter vs Validator?

The formatter validates first, then formats. The JSON Validator gives you more detailed error info without formatting. This tool does both in one step.

Which indentation?

2 spaces for JavaScript/TypeScript/Node.js. 4 spaces for Python/Java. Tabs if your team prefers them. Whatever your .editorconfig says.