JSON Validator
Validate JSON syntax and find errors instantly in your browser. Your data never leaves your device. Free and private.
No uploads. No account. Free to use.
Paste JSON. Validation never leaves this tab.
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- Files never leave your device
- Runs entirely in your browser
- No signup required
- Free
What is JSON Validator?
JSON Validator checks whether your JSON is syntactically correct and reports exact error locations. Paste or drop a file; validation runs entirely in your browser so your data stays private.
Key features
- Instant syntax checking
- Clear error messages with location
- 100% client-side
- No account required
- Works with large payloads
- Complements the JSON Formatter
How to use it
- Open the JSON Validator.
- Paste JSON or drop a file.
- See instant validation result and any error messages with line numbers.
- Fix and re-validate as needed. Nothing is uploaded.
When to use it
Use JSON Validator when debugging API responses, config files, or any JSON that must be valid before further processing — especially sensitive data.
In this family
JSON tools — related tools in the same cluster.
Frequently asked questions
Related tools
More in Data tools.