JSON, Quick Facts
- •JSON stands for JavaScript Object Notation, the standard data format for APIs, config files, and NoSQL databases.
- •Valid JSON requires double quotes around keys and strings, no trailing commas, and no comments.
- •The only types allowed are object
{}, array[], string, number, boolean, andnull. - •A single missing comma or bracket is the most common cause of "Unexpected token" errors.
The Real Problem This Solves
APIs and log files return JSON crammed onto one line, hundreds of characters wide, with no indentation. Reading it, or spotting the one syntax error breaking your integration, is nearly impossible by eye.
This tool beautifies it instantly for reading, or minifies it back down for production, and tells you exactly where a syntax error is hiding instead of a vague browser console error.
How JSON Formatting Works
Formatting parses your JSON into a data structure, then rewrites it with consistent indentation, line breaks, and, optionally, alphabetically sorted keys. Minifying reverses this: it strips all whitespace to produce the smallest possible payload for the wire.
Example: A minified API response like {"id":7,"name":"Rahul","active":true} expands into a clean, indented block with one key per line, making nested objects and arrays immediately readable, especially useful for deeply nested config files or GraphQL responses.
| Character | Escape Sequence | Used For |
|---|---|---|
| Double quote | \" | A literal quote inside a string |
| Backslash | \\ | A literal backslash |
| Newline | \n | A line break inside a string |
| Tab | \t | A tab character inside a string |
Frequently Asked Questions
Why does my JSON say "Unexpected token"?
Usually a trailing comma, single quotes instead of double quotes, or an unquoted key. This tool shows the exact line and column of the failure so you can jump straight to it instead of scanning the whole file.
Can JSON have comments?
No. The JSON specification has no comment syntax. If you need notes, use a JSON5/JSONC-style variant your tooling supports, or add a dedicated field like "_comment".
What is the difference between JSON and a JavaScript object?
JSON is a text format with a stricter subset of rules: quoted keys, no functions, no trailing commas, no undefined values. A JavaScript object literal is code and can hold any value, including functions, that JSON simply cannot represent.
Is my data sent to a server?
No. Formatting, minifying, and validation all happen entirely in your browser using JavaScript's built-in JSON parser. Nothing is uploaded anywhere.
Does sorting keys change what the JSON means?
No. JSON objects are unordered by specification, so sorting keys alphabetically only affects readability and makes diffs cleaner, it does not change the data. Array order is always preserved.
Working with an encoded token or payload?
JWT tokens and many API payloads are Base64-encoded JSON under the hood. Decode one first with our Base64 Encoder/Decoder, then paste the result here to pretty-print it.
Open Base64 Encoder/Decoder →