JSONPath Tester

What it does

JSONPath selects nodes from a document. The two things that go wrong are selecting nothing and selecting more than expected, so the count is as much the answer as the values.

Parse the document, evaluate the expression, and return every match with its path. Report the count, and distinguish an empty match from a syntax error.

Why it works this way

An expression that matches nothing and an expression that is malformed produce very different situations, and a tester that shows an empty result for both has hidden the useful half.

The count matters because most JSONPath mistakes are over-selection: a wildcard that was meant to be narrow returns fifty nodes where one was expected, and the values alone look plausible.

The root expression selects the whole document. That is the degenerate case with an answer nobody has to compute, and it is what tells you the evaluator is wired to the document at all.

Examples

$.store.book[*].author

4 matches: $.store.book[0].author … [3].author

$.nope

0 matches (not an error)

Inputs and outputs

• JSON document
• JSONPath expression

• every matching node, with its path
• the match count
• or the expression error

Edge cases

• $ with no document
• malformed expression — error, not 0 matches
• recursive descent ..
• filters with comparisons
• matches inside arrays vs objects

Sources

• RFC 9535, JSONPath: Query Expressions for JSON