JSONPath is a query language for JSON, modelled on XPath. An expression like $.store.book[0].title navigates into a document and returns the nodes it selects. It is widely used in API testing, config tooling and tools like Kubernetes kubectl.

Which JSONPath operators does this tester support?

It supports the root $, dot and bracket key access, array indices, unions like [0,2], slices like [1:3:1], the * wildcard, recursive descent .., and filter expressions such as [?(@.price , >= and =~ for regex.

Is my JSON sent to a server?

No. The expression is parsed and evaluated entirely in your browser using JavaScript. Your JSON never leaves your device, so it is safe to test sensitive payloads.

How do filter expressions work?

A filter like [?(@.price < 10)] keeps only the array elements where the condition is true. @ refers to the current element, so @.price reads its price field. You can compare against numbers, quoted strings, booleans or null.

Why does my expression return an empty array?

An empty result means no node matched. Common causes are a mistyped key, an out-of-range index, or a filter whose condition is never true. Build the path up one segment at a time to see where it stops matching.

JSONPath Tester — Gera Tools

Q: Why does my expression return an empty array?

An empty result means no node matched. Common causes are a mistyped key, an out-of-range index, or a filter whose condition is never true. Build the path up one segment at a time to see where it stops matching.

JSONPath is a compact query language for JSON documents, modelled on XPath for XML. An expression such as $.store.book[*].author describes a path from the root of a document down to the nodes you care about, and returns every value that matches. This tester evaluates JSONPath expressions live against your own JSON, entirely in the browser, so you can iterate on a query without writing any code.

How it works

A JSONPath expression is a sequence of steps applied left to right, starting from the root $. Each step takes the set of nodes selected so far and produces a new set:

.name or ['name'] selects a child property.
[0] selects an array element by index; negative indices count from the end.
[0,2] is a union that selects several indices at once.
[1:4] is a slice; an optional third value [1:9:2] sets the step.
* is a wildcard that selects every child of an object or array.
.. is recursive descent: it matches the current node and everything nested below it, so $..price finds every price anywhere in the tree.
[?(@.field op value)] is a filter that keeps only elements where the condition holds. Here @ is the element being tested.

The evaluator threads a list of candidate nodes through each step and collects whatever survives the final step as the result array.

Example

Given a store document with a book array, the expression $.store.book[?(@.price < 10)].title first walks to store, then book, keeps the books whose price is under 10, then reads each surviving book’s title. The result is the list of cheap-book titles. Change the comparison to >= 10 and the result flips to the expensive titles instead.

Tips

Build a path one segment at a time. If $.store.book returns the array but $.store.book[*].title returns nothing, the problem is the title key, not the earlier path.
Use .. when you do not know the exact depth of a value — $..id will surface every id regardless of nesting.
Filters compare against literals: numbers (10), quoted strings ('fiction'), true, false, or null. Use =~ /pattern/i to match a string field against a regular expression.