JSONPath evaluator | eyeo Developer Documentation

Overview

A lightweight JSONPath engine is supported within the json-prune, json-override, replace-xhr-response, replace-xhr-request, and replace-fetch-request snippets. This allows for precise targeting of properties within JSON objects using standard path notation.

To use JSONPath in a filter, prefix the path argument with jsonpath(. If the prefix is omitted, the snippet falls back to its standard behaviour.

Supported Syntax

Operator	Name	Description	Example
`$`	Root	Represents the root object of the JSON structure.	`$.data`
`.`	Dot Access	Accesses a child property by name.	`$.store.book`
`..`	Recursive descent	Searches for a key at any level of the hierarchy.	`$..ad_id`
`*`	Wildcard	Matches all child properties or array elements.	`$.items[*]`
`[]`	Bracket notation	Used for keys with special characters, indexes, or filter expressions.	`$['complex-key']`
`[?()]`	Filter expression	Filters objects based on a property comparison.	`[?(@.type=='ad')]`

Filter Comparison Operators

Within a [?()] expression, the following comparison operators are supported:

Equality / Inequality: ==, !=
Numeric / Lexical: <, <=, >, >=
String matching: ^= (starts with), $= (ends with), *= (contains)

Quoting a string inside a filter expression

The operator table above shows plain JSONPath. Inside an actual filter, the quotes around a string have to be written \', because the snippet filter parser treats a bare ' as a quote toggle and strips it — [?(@.type=='ad')] would reach the engine as [?(@.type==ad)]. For the same reason, a value containing a space needs surrounding single quotes so it stays one parameter. See Snippets Overview for the full escaping rules.

Examples

Filter	Result
`example.com#$#json-prune jsonpath($..ad_tracking)`	Removes every instance of `ad_tracking` found at any depth.
`example.com#$#json-override jsonpath($.items[?(@.is_sponsored==true)].label) 'Clean Content'`	Overrides the `label` property to `Clean Content` only on items where `is_sponsored` is `true`. The single quotes keep the value as one parameter.
`example.com#$#json-prune jsonpath($.metadata.*)`	Removes all properties within the `metadata` object.
`example.com#$#json-prune jsonpath($..trackingId)`	Removes every instance of `trackingId` at any depth.
`example.com#$#json-override jsonpath($.ads[?(@.type==\'banner\')].visible) false`	Sets `visible` to `false` on all banner-type ad objects. The inner quotes are escaped so the parser passes them through.