JSON Formatter & Viewer
Format, validate, and explore JSON data with a full-featured editor and interactive tree view.
How to Use This Tool
- 1
Paste your raw or minified JSON into the editor on the left side.
- 2
The formatter will automatically validate and pretty-print your JSON with syntax highlighting.
- 3
Use the tree view panel to collapse and expand nested objects and arrays for easier exploration.
- 4
Click the Copy button to copy the formatted JSON to your clipboard, or use Minify to compact it back to a single line.
What is JSON?
JSON (JavaScript Object Notation) is a lightweight, human-readable data interchange format originally derived from JavaScript object syntax. It has become the dominant format for transmitting structured data across the web — used in REST APIs, configuration files, NoSQL databases, and virtually every modern application stack. Its simplicity and language-agnostic nature make it the go-to choice when systems need to exchange data.
A JSON document is built from just two structures: objects (key/value pairs enclosed in curly braces) and arrays (ordered lists enclosed in square brackets). Values can be strings, numbers, booleans, null, nested objects, or nested arrays. This small surface area is a large part of why JSON became so ubiquitous — it maps naturally onto data structures in nearly every programming language.
Formatting and validating JSON is a daily task for developers. Minified or machine-generated JSON is almost impossible to read directly, and a single misplaced comma or missing quote will cause a parse failure. A JSON formatter instantly pretty-prints raw JSON into an indented, readable form and catches syntax errors so you can fix them before they become runtime bugs.
Frequently Asked Questions
helpIs my JSON data sent to a server?
No. All formatting, validation, and tree-rendering happens entirely in your browser using JavaScript. Your data never leaves your machine.
helpWhy does my JSON fail to validate?
Common causes include trailing commas after the last item in an object or array (not allowed in JSON), single quotes instead of double quotes around strings, unquoted keys, or comments (JSON does not support comments). The editor will highlight the offending line.
helpWhat is the difference between JSON and JavaScript objects?
JSON is a text format — a strict subset of JavaScript. JavaScript objects support unquoted keys, single quotes, trailing commas, and non-serialisable values like functions. JSON requires double-quoted keys and string values, no trailing commas, and only supports strings, numbers, booleans, null, objects, and arrays.
helpCan I format very large JSON files?
Yes. Because processing runs locally in your browser there is no file size limit imposed by a server. Performance depends on your device; very large files (tens of megabytes) may take a moment to render the tree view.