JSON Validator
ValidatorValidate JSON syntax with detailed error messages and structure analysis.
Actions
What is This Tool?
A JSON validator checks JSON data for syntax errors, structural issues, and format compliance. Get precise error locations with line and column numbers, helpful error messages, and auto-fix suggestions for common JSON mistakes like trailing commas and unquoted keys.
Valid JSON per RFC 8259 requires: double-quoted strings only, no trailing commas, no comments, no undefined/NaN/Infinity values, and properly nested brackets/braces. This validator catches all these issues and provides actionable error messages for quick fixing.
Common Use Cases
API Debugging
Validate JSON payloads from API requests and responses to find syntax errors causing parsing failures.
Config File Checking
Validate package.json, tsconfig.json, and other JSON config files that cause cryptic errors when malformed.
Data Pipeline QA
Validate JSON data at pipeline boundaries to catch malformed records before they cause downstream failures.
Content Migration
Validate JSON exports from databases and CMS platforms before importing into new systems.
Frequently Asked Questions
What errors are detected?
Missing/extra commas, unquoted keys, single quotes, trailing commas, comments, special values (undefined, NaN), mismatched brackets, and encoding issues.
Can it fix errors automatically?
Common fixes (removing trailing commas, adding missing quotes) can be suggested. Complex structural errors require manual correction.
Is JSON5 or JSONC validated?
This validates strict JSON per RFC 8259. JSON5 features (comments, trailing commas) are flagged as errors. Use a JSON5 validator for those formats.