JSON Query は何をしますか？
JSON Query はブラウザ上でデータを調査するツールで、結果と制限を明確に示します。 検証済みの機能： Nested field extraction, Array filters and projections, JSON file input and export, Cancellable local Worker.
When should you use this tool?
Use JSON Query to select or reshape data. Use JSON Formatter to inspect syntax and JSON Diff to compare complete documents. Keep the original file when exact numeric lexemes matter.
使い方
- Paste JSON or open a local JSON file up to 2 MiB.
- Enter an expression such as users[?age >= `18`].name and select Run.
- Check the result, then copy or download it; run again after changing the input or expression.
実際の入出力例
Extract adult users by name
入力
{"users":[{"name":"Ada","age":32},{"name":"Linus","age":17}]}
Expression: users[?age >= `18`].name出力
[
"Ada"
]The filter selects users whose age is at least 18 and projects their name values.
一般的なエラーと対処
| 症状 | 原因 | 対処 |
|---|---|---|
| A missing field returns null. | The selected path does not exist in this JSON value. | Inspect the document structure and spelling; null can be a valid query result. |
| The expression reports a syntax error. | JMESPath syntax differs from JavaScript and JSONPath. | Use backticks for JSON literals and double quotes around nonstandard identifiers. |
Supported behavior and limitations
このツール固有の制限： This tool uses JMESPath Community syntax, not JSONPath or arbitrary JavaScript. JSON numbers use ordinary JavaScript precision; keep large IDs as strings. No network requests from expressions are supported.
標準と実装の参考資料
- JMESPath Community TypeScript implementation (opens in a new tab)Browser-compatible query interpreter; the adopted version is recorded in the tool inventory.
- JMESPath tutorial (opens in a new tab)Explains projections, filters, expressions, and identifiers.
JSON Query — FAQ
Is my input uploaded?
No. Processing happens in a browser Worker. Engine files load from this website; tool input, output, and filenames are not sent to a processing API.
Do I need an account or API key?
No account, API key, or backend processing service is needed.
How do I save a result?
Review the result, then use the Copy or Download control available for that output. Modifying input clears stale results.
What are the limits?
This tool uses JMESPath Community syntax, not JSONPath or arbitrary JavaScript. JSON numbers use ordinary JavaScript precision; keep large IDs as strings. No network requests from expressions are supported.
更新内容
実質的な更新： JSON Query: Added local processing, explicit size limits, cancellation, worked examples, error explanations, and downloadable results.