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JSON Validator
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Free online JSON validator and syntax checker
This JSON validator checks whether your JSON is syntactically correct and, when it isn't, tells you exactly where the problem is - including the line and column of the error whenever the browser reports a position. It catches the classic mistakes: trailing commas, single quotes instead of double quotes, unquoted property names, missing brackets and stray control characters.
Common JSON syntax errors
- Trailing commas -
{"a": 1,}is valid JavaScript but invalid JSON. - Single quotes - JSON strings and keys must use double quotes.
- Unquoted keys -
{name: "x"}fails; keys need quotes. - Comments - JSON does not allow
//or/* */comments. - NaN / undefined - only
null, numbers, strings, booleans, arrays and objects are allowed.
Why validate JSON before shipping?
A single malformed character can break an API integration, a CI pipeline reading a config file, or a mobile app parsing a response. Running a quick JSON lint before you commit a config or publish an endpoint saves debugging time downstream. This checker runs 100% locally in your browser - nothing you paste is uploaded - so it is safe for payloads containing tokens or personal data.
Once your JSON is valid, pretty-print it with the JSON formatter, compress it with the JSON minifier, or generate typed models with theJSON to TypeScript converter.