JSON Validator
What is JSON Validation?
JSON validation checks whether a text document follows the JSON grammar: double-quoted strings, valid punctuation, legal values, escaped control characters, and balanced objects or arrays. Syntax validation is the first step before an API payload, config file, package manifest, or fixture can be trusted by another tool.
JSONFather validates JSON in the browser and reports line and column information for parse errors. It also warns about duplicate object keys and summarizes document statistics, so you can spot risky payloads before they reach a build, deployment, or production API.
How to Validate JSON
Paste JSON into the validation editor and choose Validate JSON. If the document is valid, review the statistics and duplicate-key warnings. If it is invalid, use the reported line and column as a starting point, then inspect the token just before the error because parsers often detect a problem after the original typo.
Available actions
- Validate JSON
- Import JSON file
- Copy output
- Download output
- Create expiring JSON share link
- Collapse all
- Expand all
- Escape JSON string
- Unescape JSON string
- Generate sample JSON
- Simple sample
- Medium sample
- Complex sample
- Back to top
- Back to bottom
- Find in editor
- Previous match
- Next match
- Replace all
- Close search panel
Example
Input
{"user":{"id":1,"name":"Ada"},"active":true}Output
Valid JSON
Objects: 2
Arrays: 0
Keys: 4FAQ
Does this validate JSON Schema?
No. This page validates JSON syntax only. JSON Schema validation is planned as a separate tool.
Are duplicate keys valid JSON?
JSON parsers usually accept them, but later keys overwrite earlier values. jsonfather warns you when it sees duplicates.
Can I validate private configuration files?
Yes. Validation runs locally in your browser and does not upload your input.