JSONPath: Query JSON Data Like a Pro

What is JSONPath?

JSONPath is a query language for JSON, analogous to XPath for XML. It lets you select one or more values from a JSON document using a compact path expression — without writing a loop or knowing the exact structure in advance.

JSONPath is used in: - Postman — extract values from API responses in test scripts - AWS Step Functions — InputPath, OutputPath, and ResultPath all use JSONPath - Kubernetes — kubectl jsonpath output format for scripting - Gatling, k6, RestAssured — API load and contract testing - Grafana Transformations — extracting fields from JSON data sources

JSONPath Syntax Reference

Every expression starts with $ — the root of the document.

Expression	Meaning
`$`	Root document
`$.key`	Property "key" on the root object
`$.a.b.c`	Nested property — a.b.c
`$.arr[0]`	First element of array "arr"
`$.arr[-1]`	Last element (negative index)
`$.arr[*]`	All elements of array "arr"
`$.*`	All properties of the root object
`$..name`	Recursive descent — "name" anywhere in the document
`$.arr[0:3]`	Slice — elements at index 0, 1, 2
`$.arr[::2]`	Every second element
`$.arr[-2:]`	Last two elements

Recursive Descent (`$..key`)

The \.. operator descends into every level of the tree and returns all values with the given key — regardless of how deeply nested they are.

json

{
  "order": {
    "id": 1001,
    "items": [
      { "product": { "name": "Laptop" },  "qty": 1 },
      { "product": { "name": "Monitor" }, "qty": 2 }
    ]
  }
}

$..name   →  ["Laptop", "Monitor"]
$..qty    →  [1, 2]

No loop needed. The expression works even if the nesting changes in future API versions.

Filter Expressions `[?(@.condition)]`

Filters select array elements matching a condition. The @ refers to the current item being tested:

$.books[?(@.price < 30)]            — books under $30
$.users[?(@.status == "active")]    — active users only
$.orders[?(@.total >= 1000)]        — high-value orders
$.items[?(@.tags)]                  — items that have a "tags" field
$.items[?(@.discount && @.qty > 5)] — items with discount AND qty > 5

Supported comparison operators: ==, !=, <, <=, >, >=

Complete Practical Example

Given this API response:

json

{
  "store": {
    "name": "Tech Books",
    "book": [
      { "title": "Clean Code",      "author": "Martin", "price": 29.99, "inStock": true  },
      { "title": "Refactoring",     "author": "Fowler", "price": 34.99, "inStock": false },
      { "title": "Design Patterns", "author": "GoF",    "price": 39.99, "inStock": true  }
    ]
  }
}

Expression	Result
`$.store.name`	"Tech Books"
`$.store.book[*].title`	["Clean Code", "Refactoring", "Design Patterns"]
`$..author`	["Martin", "Fowler", "GoF"]
`$.store.book[0].price`	29.99
`$.store.book[-1].title`	"Design Patterns"
`$.store.book[0:2].title`	["Clean Code", "Refactoring"]
`$.store.book[?(@.price < 35)].title`	["Clean Code", "Refactoring"]
`$.store.book[?(@.inStock == true)].title`	["Clean Code", "Design Patterns"]
`$.store.book[?(@.price < 35 && @.inStock)].title`	["Clean Code"]

JSONPath in JavaScript

javascript

// npm install jsonpath-plus
import { JSONPath } from "jsonpath-plus";

const data = { store: { book: [{ title: "Clean Code", price: 29.99 }] } };

// Get all book titles
const titles = JSONPath({ path: "$.store.book[*].title", json: data });
// => ["Clean Code"]

// Get books under $35
const cheap = JSONPath({ path: "$.store.book[?(@.price < 35)]", json: data });

JSONPath in Python

python

# pip install jsonpath-ng
from jsonpath_ng import parse
import json

with open("data.json") as f:
    data = json.load(f)

# Find all book titles
expr = parse("$.store.book[*].title")
titles = [match.value for match in expr.find(data)]
print(titles)  # => ["Clean Code", ...]

# Filter by price
expr2 = parse("$.store.book[?(@.price < 35)].title")
cheap = [m.value for m in expr2.find(data)]

JSONPath in Postman

In Postman test scripts, use pm.response.json() and chain with JSONPath: