JSON Validator Online
Validate JSON syntax and pinpoint errors instantly
Cómo usar JSON Validator
- 1
Paste your JSON
Enter or paste any JSON string into the editor.
- 2
Click Validate
The tool immediately checks your JSON against the RFC 8259 specification.
- 3
Read the result
A green ✓ confirms valid JSON. A red ✗ shows the exact error location and message.
Preguntas frecuentes
Is my data safe?
What makes JSON invalid?
Does it support JSON5 or JSONC?
Can I validate large JSON files?
Saber más
¿Qué es JSON Validator?
Validate JSON syntax instantly and get precise error messages with exact line numbers. Paste any JSON string — from API responses to config files — and know in seconds whether it's valid. The validator uses the browser's native JSON parser, which strictly follows RFC 8259 and reports accurate error locations. 100% client-side: your data never leaves your browser.
¿Por qué usar JSON Validator?
- Instant validation — know immediately whether your JSON is valid or not, no waiting.
- Precise error messages — syntax errors show exact line and character positions so you can fix them fast.
- Strict RFC 8259 compliance — catches trailing commas, unquoted keys, and other non-standard syntax.
- Client-side processing — your JSON (API keys, tokens, sensitive config) never leaves your browser.
- No installation — works in any modern browser without plugins or sign-up.
Casos de uso de JSON Validator
API payload validation
Validate JSON before sending it to an API. Catch missing commas, unclosed brackets, and other syntax errors before they cause 400 errors.
Webhook debugging
Paste incoming webhook payloads to verify they are well-formed JSON before processing.
Config file checking
Validate package.json, tsconfig.json, or other config files before committing to catch typos.
Data pipeline validation
Check JSON data files before importing into databases, data warehouses, or ETL pipelines.
Consejos y buenas prácticas
- 💡The most common JSON mistake is a trailing comma after the last item in an array or object — this is not allowed in standard JSON.
- 💡JSON keys must be double-quoted strings. Single quotes are not valid.
- 💡After validating, use the JSON Formatter to pretty-print your JSON for easier reading.
- 💡JSON does not support comments — use YAML if you need commented configuration files.
Cómo funciona
Validation uses JavaScript's native JSON.parse() which strictly implements RFC 8259. Error messages come directly from the V8 engine's JSON parser, providing accurate line and column numbers. No third-party libraries are used.
Más información