JSON Tools for Developers
Validate JSON syntax, fix common errors, and format your data. All tools run in the browser. No signup required.
Main tools
- JSON Validator Online— Validate, format, minify JSON. Get line/column errors.
Error guides
Step-by-step guides to fix common JSON errors. Each includes causes, solutions, and examples.
- JSON Unexpected Token Error
- JSON Missing Bracket
- JSON Trailing Comma Error
- JSON Duplicate Keys
- JSON Invalid Escape Sequence
- JSON Unquoted Keys
- JSON Single Quotes Not Allowed
- JSON Empty String vs Null
- JSON Invalid Number Format
- JSON Invalid Unicode Escape
- JSON null vs Empty
- JSON Array vs Object
- JSON Nested Depth
- JSON Unclosed String
- JSON Control Character
- JSON Hex Number
- JSON Leading Zero
- JSON Comments
- JSON BOM
- JSON Line Ending
- JSON Unicode Escape
- JSON Large Number
- JSON Scientific Notation
- JSON Infinity NaN
- JSON Date Format
- JSON Key Order
- JSON Whitespace
- JSON Tab in String
- JSON Mixed Types
- JSON Comma After Last
- JSON Missing Colon
- JSON Extra Comma
- JSON Invalid Value
- JSON Too Long
- JSON Encoding
- JSON Invalid Unicode
- JSON Escaped Slash
- JSON Multiline String
- JSON Sparse Array
- JSON Circular Reference
Related tools
- API Response Checker — validate JSON from API responses
- CSV Validator — validate CSV (often used with JSON)
- YAML Validator — validate YAML config
FAQ
- What is the best JSON validator?
- Our JSON Validator checks syntax, reports line/column errors, and supports format/minify. No signup required.
- How do I fix JSON unexpected token?
- See our Unexpected Token guide for causes and solutions.
- Is there a JSON validator API?
- Yes. See API Documentation for
POST /api/v1/validate/json.