JSON Validator
Check JSON syntax and see the shape of your data
上に入力すると結果が表示されます。
すべての処理はブラウザ内で完結します。データが端末外に送信されることはありません。
関連ツール
使い方
Validation uses the browser's native JSON parser, so what it accepts is exactly what your application will accept. There is no dialect or leniency difference to trip over.
Paste the JSON to check
Validation runs as you type. There is no submit step, so fixing an error and seeing it clear is immediate.
Read the error, then the line
When parsing fails you get the parser's own message plus the line it stopped on. The message names what it expected; the line tells you where.
Use the structure summary
For valid JSON, the key count, nesting depth and object and array counts describe the shape at a glance — useful for spotting a payload that is deeper or larger than you assumed.
使用例
Catching a trailing comma
The array ["a", "b",] is valid JavaScript but invalid JSON. The validator reports the unexpected token and the line, which is the most common failure in hand-edited config files.
Checking an unfamiliar API payload
A response reporting 240 keys across a maximum depth of 6 tells you immediately that flat destructuring will not work and you need a recursive walk or a schema.
このツールについて
Validate JSON and get the failure line when it is malformed. Valid documents are summarised by structure — total keys, maximum nesting depth, and how many objects and arrays they contain — which is a fast way to sanity-check an unfamiliar payload before writing code against it.