What RFC 9535 Standardizes
RFC 9535 gives JSONPath query expressions an IETF Standards Track definition. The RFC describes a string syntax for selecting and extracting JSON values from a JSON value, covering the root node, child and descendant segments, selectors, filters, and function extensions.
That matters because JSONPath has been used across libraries and developer workflows for years. A common specification gives tool authors a reference point when a query moves between an API client, a test fixture, a browser utility, and a runtime library.
Why JSON Payload Debugging Benefits
Large API responses often need a focused question before they need a rewrite: find matching objects, inspect a nested field, or compare a subset of an array. JSONPath is aimed at that selection step, so a formatter or diff workflow can stay centered on the part of a payload that needs attention.
For local-first browser tools, the standard is also useful as a boundary. A query can be evaluated against pasted JSON in the tab, while the payload remains local and the query semantics come from a public specification instead of a library-specific convention.
JSONPath and JSON Pointer
RFC 9535 explicitly positions JSONPath alongside JSON Pointer rather than as a replacement. JSON Pointer identifies a location with a compact path. JSONPath can express broader selections, such as wildcard traversal, descendants, slices, and filters that can return more than one matched node.
That distinction is practical in developer tools. Pointer-style paths fit exact references in patches and diagnostics, while JSONPath fits exploratory payload inspection when the matching values depend on structure or predicates.
What Tool Authors Should Check
Existing JSONPath implementations may have grown around older behavior, so the first step is to compare query parsing and result behavior with RFC 9535 before promising standards compatibility. Filters, function extensions, result ordering, and normalized paths deserve particular attention when queries cross library boundaries.
The JSONPath working group says its adopted work is complete. That makes RFC 9535 the document to keep beside JSON parsing, validation, and diff tooling when JSON selection behavior needs to be explained precisely.