How jsonpath extractor works
JSONPath is a query language for JSON, similar to how XPath works for XML. You write a path expression starting with $ (the root) and the extractor walks the parsed JSON, returning every value the path matches along with the exact path to each value so you can see where it came from.
The extractor supports the common JSONPath syntax: .name or ['name'] for object members, [n] for array indexes (negative indexes count from the end), [*] (and .*) as a wildcard matching every element of an array or every value of an object, [start:stop:step] for slices, ..name for recursive descent that finds a member anywhere below the current node, and filters like [?(@.price < 10)] that select array elements by a comparison on their fields. Combine these to reach deeply nested values.
Because every computation runs in your browser, your JSON never leaves your device. The extractor returns each match's path and value; for objects and arrays the value is serialized back to JSON so you can read it at a glance.