JSON Beautify
Instantly format and beautify your JSON with customizable indentation (2 or 4 spaces). Makes minified JSON readable.
JSON Formatter Online
Lines —Chars —Size ——
Paste JSON data on the left to see formatted json
The Fastest Way to Format JSON Online
Online Data Tools JSON Formatter is a free, browser-based JSON beautifier and validator that instantly formats, minifies, and validates your JSON data. Whether you're debugging API responses, cleaning up configuration files, or working with large datasets, our tool makes it effortless.
Key Features
JSON Validation
Validate JSON syntax with detailed error messages and line numbers. Quickly find and fix malformed JSON.
Syntax Highlighting
Color-coded output with syntax highlighting for keys, strings, numbers, booleans, and null values.
Tree View
Explore JSON structure with an interactive collapsible tree view. Expand and collapse objects and arrays at any depth.
Large File Support
Handles 10,000+ line JSON files without freezing your browser. Optimised tokenizer and virtual rendering.
100% Private
All processing runs entirely in your browser. No data is ever sent to a server. Your JSON stays private.
How It Works
1
Paste or Upload JSONPaste your JSON into the editor or upload a .json file.
2
Click FormatHit the Format button to beautify, or Minify to compress. Validate to check syntax.
3
Copy or DownloadCopy the formatted output to clipboard or download as a file.
Common Use Cases
API Response Debugging
Format and read API responses from REST and GraphQL endpoints. Spot issues in deeply nested JSON payloads instantly.
Config File Validation
Validate and debug configuration files like package.json, tsconfig.json, and .eslintrc with syntax error details.
Data Import Preparation
Validate JSON data before importing into databases. Catch syntax issues early to prevent failed ingestion jobs.
Payload Optimization
Minify JSON for smaller payloads and faster API transfers. Explore nested structures with the interactive tree view.
Frequently Asked Questions
Is this JSON formatter free?
Yes! Online Data Tools JSON Formatter is completely free with no sign-up, no ads, and no usage limits.
Is my JSON data safe?
Absolutely. All processing happens in your browser. No JSON data is ever sent to our servers.
Can it handle large JSON files?
Yes. The formatter is optimised for large JSON files with 10,000+ lines. It uses efficient tokenization to avoid browser freezing.
What's the difference between Format and Minify?
Format (beautify) adds indentation and line breaks to make JSON readable. Minify removes all whitespace to make JSON as compact as possible, reducing file size.
Does it validate JSON?
Yes. Click the Validate button to check your JSON syntax. If there are errors, you'll see the exact line and column number where the problem occurs.