JSON Validator & Syntax Checker
Instantly validate JSON syntax, identify errors with exact line and column locations, and fix formatting bugs.
Batch workspace
Format multiple files locally in one run.
How to use the JSON Validator
Paste code or file
Paste your raw JSON text or upload directly.
Configure options
Choose indentation, dialect, or formatting preferences.
Format & export
Click format, then copy, download, or inspect in tree view.
What is a JSON Validator?
Instantly validate JSON syntax, identify errors with exact line and column locations, and fix formatting bugs. This tool re-indents and organizes code according to standard style conventions while checking for syntax validity. Everything executes 100% inside your browser, guaranteeing zero latency and complete privacy for API keys, user tokens, and confidential database schemas.
Options Explained
| Option | Description |
|---|---|
| Validation Mode | Choose whether to output clean formatted JSON, compressed JSON, or a validation confirmation summary. |
| Indent Size | Number of spaces per indentation level when beautifying. |
Frequently Asked Questions
How does the JSON validator detect errors?
The validator parses your JSON client-side using JavaScript parsing engines and analyzes syntax tokens to pinpoint exact line and column numbers.
What are the most common JSON syntax errors?
Trailing commas after the last array item or object property, unquoted property keys, single quotes instead of double quotes, and unescaped newline characters.
Is my validated JSON uploaded to any server?
No. All validation runs 100% locally in your browser memory. No text or telemetry is ever transmitted to a server.
Can this validator format and beautify the JSON if valid?
Yes. By default it automatically beautifies valid JSON with clean 2-space indentation. You can switch to Compact or Validate-Only mode in options.
What is the maximum JSON file size supported?
Files up to 5MB are parsed instantly in the browser. Payloads larger than 500KB are processed asynchronously to ensure UI smoothness.
Free Developer Cheat Sheet
Download a handy, printable reference guide for JSON Validator syntax and best practices.
Download Free Cheat Sheet