JSON Formatter & Validator
This JSON formatter and validator beautifies, minifies, and validates JSON right in your browser. Paste or upload JSON and the output appears instantly with syntax highlighting and real-time error checking — no installs, no sign-up.
You get two ways to read your data: a color-coded Code view for scanning formatted JSON, and a collapsible Tree view for exploring nested objects and arrays. When something is wrong, validation pinpoints the exact line and column so you can fix it fast.
How to Format and Validate JSON
Add your JSON
Paste your JSON into the Input panel on the left, click Upload File to load a .json or .txt file, or hit Sample Data to try it out. The formatted output appears automatically.
Format or minify
Choose Format to beautify the JSON with clean indentation, or Minify to compress it onto a single line. In Format mode, pick an indent size of 2, 4, or 8 spaces.
Check validity
The status bar shows Valid JSON or Invalid JSON as you type. If there is an error, the exact line and column appear and the offending line is highlighted in the editor.
Explore, copy, or download
Switch to the Tree tab to browse nested data with collapsible nodes, then use Copy, Download, or Clear to finish up.
Features
Format & Minify Modes
Toggle between beautifying JSON with readable indentation and compressing it to a compact single line.
Configurable Indentation
Choose 2, 4, or 8 spaces of indentation to match your project's style.
Real-Time Validation
JSON is validated as you type, with the exact line and column of any syntax error shown and highlighted.
Syntax Highlighting
Keys, strings, numbers, booleans, and null values are color-coded so data is easy to scan.
Collapsible Tree View
Explore nested JSON as a hierarchy, with type badges like Object{5} and Array[3] on each node.
Upload Files
Load JSON directly from your device using .json or .txt files.
Download Output
Save the formatted result as a .json file with one click.
Copy to Clipboard
Copy the formatted JSON to your clipboard instantly, ready to paste anywhere.
Sample Data
Load a ready-made example to try the tool without preparing your own JSON.
Live Statistics
The status bar reports line count, file size, and the total number of keys across all nested objects.
Frequently Asked Questions
How do I format or beautify JSON online?
Paste your JSON into the Input panel and the formatted result appears automatically. Make sure Format mode is selected, then pick an indent size of 2, 4, or 8 spaces. Beautifying adds proper indentation and line breaks so a one-line blob like {"name":"John","age":30} becomes a readable, multi-line structure.
How do I validate JSON and find syntax errors?
Validation runs as you type. The status bar shows Valid JSON or Invalid JSON, and when there is a problem the error message reports the exact line and column and highlights that line in the editor — so you can jump straight to the issue.
What causes an "invalid JSON" error?
The most common culprits are a missing or extra comma, an unmatched bracket or brace, unquoted keys, single quotes instead of double quotes, a trailing comma after the last element, and comments — JSON does not support comments. The error position points you to where the parser stopped.
What is the difference between format and minify?
Format (beautify) adds indentation and line breaks to make JSON human-readable. Minify strips out every unnecessary space, tab, and newline to shrink the file to its smallest size — handy for sending JSON over the network or storing it where size matters.
Is there a file size limit?
There is no fixed cap. Because everything runs in your browser, the practical limit depends on your device's memory. Most modern browsers handle JSON files up to several megabytes without trouble.
Is my JSON data kept private?
Yes. All processing happens entirely in your browser using JavaScript. Your JSON is never uploaded to any server and nothing is stored or tracked, so your data stays on your device.
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