JSON Validator
Validate JSON instantly and find syntax errors with the exact line, column and position — right in your browser.
100% private — everything runs in your browser
How to Use
- 1
Paste or type your JSON into the input editor.
- 2
Click Validate to check the syntax.
- 3
If the JSON is valid, a green confirmation appears together with structure stats such as type, keys, depth and size.
- 4
If the JSON is invalid, the error is reported with its message, line, column and exact position.
- 5
Copy or download the validation report, or press Reset to start over.
Examples
Validate a well-formed object
Input
{"name": "ToolStack", "free": true}Output
✓ Valid JSON
Type: object
Keys: 2
Depth: 2
Lines: 1
Characters: 35
Size: 35 BCatch a trailing comma
Input
{"name": "ToolStack", "free": true,}Output
✕ Invalid JSON
Error: Expected double-quoted property name in JSON at position 35 (line 1 column 36)
Line: 1
Column: 36
Position: 35FAQ
What does a JSON validator do?
A JSON validator checks whether your text follows the strict JSON syntax rules. If it does, you get a confirmation plus structure statistics; if not, the exact location of the first error is reported.
Is this JSON validator free?
Yes, it is completely free — no sign-up, no limits and no ads covering the tool.
Is my JSON data sent anywhere?
No. Validation runs entirely in your browser. Your JSON never leaves your device.
What are the most common JSON syntax errors?
Missing or extra commas, unquoted keys, single quotes instead of double quotes, trailing commas, unescaped control characters, and missing closing brackets or braces. The validator points to the exact line, column and position.
Can it validate large JSON files?
Yes. The editor is built on CodeMirror, which comfortably handles documents of several megabytes on modern devices.
Does it support comments or JSON5?
No — strict JSON does not allow comments. Remove them before validating, or the validator will flag them as errors.