JSON Validator Online
Validate JSON online and find syntax errors fast. Paste your JSON to check whether it is well-formed and see the exact position of any error.
Part of the free JSON Formatter & Validator. Runs in your browser — nothing is uploaded.
JSON Validator Online
A JSON validator tells you whether a document follows the JSON specification before a parser rejects it in production. Paste your data, press Validate, and any syntax problem is reported with its position so you can jump straight to it.
Worked example: Validating a small config document
JSON to check
{"debug":false,"retries":3,"hosts":["a.example.com","b.example.com"]}Validator result
✓ Valid JSON (top-level object)
Practical tip
Valid JSON is not the same as correct data. Validation checks syntax only, so also check required fields against your schema or API docs.
How to use this JSON Formatter
- 1Use the live tool above — it runs entirely in your browser and never uploads your data.
- 2Paste the sample from the worked example, or use your own input.
- 3Copy the result, then adapt the same steps in your editor, script, or pipeline.
JSON Validator Online FAQs
What makes JSON invalid?
The usual causes are trailing commas, single-quoted strings, unquoted keys, comments, and unescaped control characters inside strings.
Can this validate JSON against a schema?
This page checks syntax. For structure checks, validate the formatted output against a JSON Schema in your own pipeline or compare two documents with the JSON diff tool.
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