How to use the JSON Validator
- Paste your JSON.
- It's checked as you type.
- If there's an error, read the line, column and explanation, then fix it.
What does this tool do?
Valid JSON follows strict rules: double-quoted keys and strings, no trailing commas, no comments, and only true, false, null, numbers, strings, arrays and objects as values. The validator checks against the official standard (RFC 8259) and explains failures in plain English.
Why use it?
- Debug API payloads and config files.
- Clear messages instead of cryptic parser errors.
- Shows structure stats when it's valid.
Common JSON errors
What the validator catches most often:
| Mistake | Invalid | Valid |
|---|---|---|
| Trailing comma | {"a": 1,} | {"a": 1} |
| Single quotes | {'a': 'b'} | {"a": "b"} |
| Unquoted key | {a: 1} | {"a": 1} |
| Python values | {"ok": True} | {"ok": true} |
| Comments | {"a": 1 // note} | {"a": 1} |
Privacy
Everything you type is processed in your browser. Nothing you enter is sent to our servers or stored by us. There's no account to create and nothing to install.
Last reviewed by the M2Toolkit team.