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JSON formatter, JSON validator and JSON decoder online
Format, minify, validate, sort keys, copy and download JSON payloads.
JSON formatter and validator
JSON formatter and validator
bytes →
JSON formatter and validator
Query parameters
IDN / Punycode
JSON formatter and validator
..
Header
Payload
Metadata
· Expires:
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Sign (HS)
JSON formatter and validator
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Replacement result
JSON formatter and validator
Relative:
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Build from parts
Difference
JSON formatter and validator
JSON formatter and validator
JSON formatter and validator
Examples
Input
{"name":"Ann","roles":["admin","editor"],"active":true}
Formatted
{
"name": "Ann",
"roles": [
"admin",
"editor"
],
"active": true
}
JSON Guides & articles
Why JSON Became the Language of Web APIs
JSON won because it made structured data easy to read, generate, and move between unrelated systems. Its success also created conventions developers now take for granted.
Read articleDesigning JSON APIs That Survive Change
A durable JSON API depends less on clever payloads than on predictable naming, explicit types, careful compatibility, and useful errors.
Read articleDebugging Invalid JSON in Real Applications
Invalid JSON is often a symptom of a broken boundary, unexpected encoding, or incorrect assumptions rather than a simple missing comma.
Read articleRelated tools
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Open URL encoder, URL decoder and query string parserJSON formatter and validator
Format, minify, validate, sort keys, copy and download JSON payloads. DevToolGrid Online offers a free JSON formatter, JSON validator and JSON decoder online.
What is JSON?
JSON (JavaScript Object Notation) is a lightweight, text-based format for exchanging data between servers and applications. It stores information as key–value pairs and ordered lists, is language-independent and is easy for both people and machines to read. A JSON formatter re-indents minified or messy JSON so its structure becomes clear.
How to format JSON
- 1 Paste or type your JSON into the input panel on the left.
- 2 Choose an indentation size — 2 spaces, 4 spaces or tabs.
- 3 Click Format to pretty-print it, or Minify to compress it to a single line.
- 4 Copy the result or download it as a .json file. Everything runs in your browser.
Common JSON errors
- Missing commaEvery key–value pair except the last must be separated by a comma. A missing comma between properties is the most common syntax error.
- Missing or extra bracketEach { or [ needs a matching } or ]. An unbalanced bracket makes the whole document invalid.
- Invalid quotesJSON keys and string values must use double quotes. Single quotes or unquoted keys are not valid JSON.
JSON Formatter vs JSON Validator
A JSON formatter focuses on readability: it indents and aligns valid JSON so you can scan it quickly. A JSON validator focuses on correctness: it checks the syntax and reports the exact line and column of any error. This tool does both — it formats valid JSON and points to the first error when the input is invalid.
FAQ
Is this tool free?
Yes. The JSON formatter is completely free, with no sign-up and no usage limits.
Is my JSON sent to a server?
No. All formatting, validation and conversion happen locally in your browser, so your data never leaves your device.
What is the maximum file size?
There is no hard limit; it depends on your device memory. Documents up to a few megabytes format instantly on a typical computer.
Can it convert JSON to other formats?
Yes. It converts JSON to and from YAML and CSV, exports XML and TypeScript types, and runs JSONPath queries.