JSON Formatter – Format, Validate & Minify JSON
Calcon's free JSON Formatter lets you format, beautify, minify, and validate JSON instantly in your browser. Switch to Tree View to explore deeply nested structures. Nothing is sent to any server.
JSON Syntax Rules
Keys must be strings
{"name": "value"} ✓ — {name: "value"} ✗
Strings use double quotes
"hello" ✓ — 'hello' ✗
No trailing commas
{"a":1} ✓ — {"a":1,} ✗
Values: string, number, bool, null, object, array
"true" vs true (boolean)
No comments
JSON does not support // or /* */ comments
Frequently Asked Questions
What is JSON and why is formatting important?
JSON (JavaScript Object Notation) is a lightweight data interchange format. Formatting (beautifying) adds consistent indentation to make it human-readable. Minifying removes all whitespace to reduce file size for transmission. Well-formatted JSON is easier to debug and review.
How do I validate JSON?
Paste your JSON into the input area and click "Validate". The tool will parse the JSON using a strict parser and report either "Valid JSON" with a green checkmark, or the exact syntax error message with a description of what went wrong.
What is JSON minification?
JSON minification removes all unnecessary whitespace, newlines, and indentation from JSON, producing a compact single-line version. This reduces payload size when sending JSON over APIs or storing it in files where human readability is not required.
What is the JSON tree view?
The tree view renders your JSON as an interactive, collapsible hierarchy. You can click any object or array node to collapse or expand it. This makes it easy to navigate deeply nested JSON structures without scrolling through raw text.
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