How to filter a JSON array and export selected fields
Paste a JSON document, enter a JMESPath expression, and run a local query. The result is JSON you can copy or download. Processing runs in a cancellable browser Worker, with a 2 MiB input limit and a 30-second timeout.
How do you do it?
- 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.
Extract adult users by name
The filter selects users whose age is at least 18 and projects their name values.
Input:
{"users":[{"name":"Ada","age":32},{"name":"Linus","age":17}]}
Expression: users[?age >= `18`].name
Output:
[
"Ada"
]When is this workflow useful?
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.
What should you check before relying on the result?
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.
What can go wrong?
| Problem | What to try |
|---|---|
| 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. |
Frequently asked questions
Do I need to upload data or sign in?
No. Processing runs in the current browser. This site serves the page and required static engine assets.
Why does the result disappear after I edit the input?
The tool clears stale output so a previous result cannot be mistaken for the new one. Run again after changing input or settings.
References
First edition: steps checked against the current tool interface, with examples and known limits.