Array index 2 selects null
Input and settings
JSON: {"a/b":{"~key":[0,false,null,""]}}
Pointer: /a~1b/~0key/2Expected result
null (a present value, not a missing path)
JSON Data Extractor
Extract a value by JSON key names or array indices. Preserve large numeric digits, then copy or save the result as JSON.
How to use
- Enter the source JSON or choose a UTF-8 file.
- Specify the location with a JSON Pointer and extract.
- Review the extracted value, then copy or save JSON.
Source JSON
Example: /users/0/name. Array indices start at 0. Leave the path empty to extract the entire document.
UTF-8 input: 2 MB; output: 5 MB. Up to 100,000 JSON values including objects and arrays, with 32 nesting levels. Path: 4,000 bytes and 32 segments. Input, filenames and results are neither stored nor sent.
Extracted JSON
Extract one value using keys and array indices
The example path /users/0 selects the first object in the users array. /users/0/name extracts "Apple"; /users extracts the whole array as JSON.
Key names distinguish case, spaces and Unicode characters. Escape / in a key as ~1, and ~ as ~0. The example path /a~1b/~0key extracts null.
For keys containing line breaks, enter the path as a JSON string, such as "/line\nbreak". URI fragments starting with #, wildcards, filters and multiple-path extraction are not supported.
Extracted strings remain quoted JSON strings. Numbers retain their digits and exponent notation. Original whitespace, indentation and string-escape spelling are not retained; output uses two-space indentation. The source file is unchanged.
Output is UTF-8 without a BOM. The preview shows the first 20,000 characters; copy and save include the entire result. Extract again after changing the source or path. Reset clears source, path and result.
Try a use case and check the result
Extract through keys containing slash and tilde, distinguishing null from an empty string.
Example buttons replace the inputs and settings above and calculate. Restore previous input steps back one example at a time. After trying multiple examples, repeat restore to return to your original input. This history is lost when the page closes.
Index 3 selects a quoted empty string
Input and settings
Same JSON / Pointer: /a~1b/~0key/3
Expected result
"" (two quote characters are output)
How to read the result
JSON Pointer escapes / as ~1 and ~ as ~0. Array indices start at zero, so 2 is the third value and 3 the fourth. Both null and empty strings are present values; strings remain quoted JSON. An empty pointer selects the whole document.
Scope and limits
Limits are 2 MB input, 5 MB output, 100,000 values, depth 32 and a 4,000-byte pointer with at most 32 segments. JSONPath, wildcards and negative indices are unsupported. Duplicate keys and invalid JSON are rejected. Preview is capped at 20,000 characters; downloads include everything. Restore returns the selected file, JSON and pointer; extract again for output.
Verification: escaped keys and zero-based indices independently identify null and the empty string. Browser checks compare original file bytes, pointer, restoration and re-extraction after two examples.
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Frequently asked questions
Can I extract null or an empty string?
Yes. Null, empty strings, false and zero are distinct from missing values. Each can be copied or saved as valid JSON.
What happens to duplicate keys or large numbers?
Duplicate keys anywhere in the input are rejected to avoid silently losing entries. Large numbers retain their original digits and exponent notation without rounding through JavaScript numbers.
Can I use 01 or -1 as an array index?
Array indices are nonnegative integers such as 0, 1 and 2. Leading zeros, negative indices and the append marker - are not supported. An object key named "01" remains a valid distinct key.
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