JSON Formatter & Validator
Beautify unformatted JSON strings, detect syntax errors, and minify payload for production.
How to Format and Validate JSON Online
JSON (JavaScript Object Notation) is the standard data format used by APIs, configuration files, and databases. Working with raw, minified JSON is difficult to read. Fixlytools JSON Formatter instantly beautifies JSON with proper indentation, detects syntax errors and shows where they occur, and can also minify JSON for production use.
- Paste Your JSON: Paste your raw or minified JSON data into the input text area on the left side of the tool.
- Click Format or Minify: Click "Format JSON" to beautify with indentation, or "Minify JSON" to compact it into a single line for production.
- Check for Errors: If your JSON has syntax errors, the tool shows the error message and, when the browser provides the position, the line and column so you can fix it quickly.
- Copy or Download: Copy the formatted output to your clipboard or download it as a .json file.
Key Features
- Real-Time Validation: Instantly detects JSON syntax errors and shows a helpful message with the error position.
- Beautify & Minify: Switch between readable, indented JSON and compact single-line JSON for production use.
- Copy to Clipboard: One-click copy of the formatted output — no selecting text manually.
- Download as File: Save the formatted or minified JSON directly as a .json file to your device.
- Private: Everything runs in your browser. No data is ever sent to any server.
Frequently Asked Questions
What is JSON formatting?
JSON formatting (or beautifying) adds proper indentation and line breaks to compact JSON data, making it easy for humans to read and debug. Minifying does the opposite — removing all whitespace to reduce file size for use in APIs and web applications.
What JSON syntax errors does the tool detect?
The tool detects common JSON errors such as missing commas, unclosed brackets or braces, incorrect quotes (JSON requires double quotes), trailing commas, and invalid values.
Is there a size limit for JSON input?
There is no strict limit, but very large JSON files (above 5 MB) may slow down the tool depending on your device. For best performance, format large JSON files in sections.
Does the tool support JSON5 or JSONC (comments)?
No. The tool validates strict JSON as defined by the JSON specification (RFC 8259). JSON5 and JSONC formats with comments are not valid JSON and will be flagged as errors.
Is my JSON data sent to a server?
No. All formatting and validation happens entirely in your browser using JavaScript. Your data is never transmitted to any server.