Home
JSON Processor

JSON Processor

Upload or paste JSON, then parse, filter, map, and transform it with simple path pipelines (like .items[].name) or JavaScript expressions (using the data variable). All processing happens locally in your browser.

Upload JSON

Click to upload or drag & drop

Supports .json files

Mode: Indent:

Expression Path mode: use .prop, [] and pipes. JS mode: use data (the parsed JSON) and return any JSON-serializable value.

Input JSON

Processed Output

Related: JSON Formatter Regex Tester

Last updated: October 2025

Help - Examples & Syntax

Path Mode (.items[].name)

Examples when data is an Array (root array)

map:x=>x.nameMap root array elements

filter:x=>x.activeFilter root array elements

filter:x=>x.price>20 | map:x=>({name:x.name,price:x.price})Filter by price and select keys

filter:x=>x.total>50 | map:x=>({id:x.id,total:x.total})Filter then map root

map:x=>x.itemsPull nested arrays out of each element

filter:x=>x.value!=null | map:x=>x.valueFilter nulls then extract field

map:x=>Object.assign({},x,{newKey:'value'}))Add new key to each element

Examples when data is an Object (dictionary)

map:x=>Object.keys(x)List all root keys

map:x=>Object.entries(x).map( ([k,v])=> [k.toUpperCase(),v] )Transform keys to uppercase

.itemsGet nested property

.items[]Iterate array property

.items[*]Iterate array with wildcard

.items[0]Get array index

.items[] | .namePipeline into property

.users[] | filter:x=>x.activeFilter array

.users[] | map:x=>x.emailMap array values

.orders[] | filter:x=>x.total>50 | map:x=>({id:x.id,total:x.total})Filter then map

JavaScript Mode (data => ... or direct)

Use data to reference the parsed JSON. If the root is an array, treat data as an array; if it's an object (dictionary), use Object.keys/Object.values/Object.entries as needed. You can return any JSON-serializable value.
Count example (works for arrays and objects):
({ count: Array.isArray(data) ? data.length : Object.keys(data).length })

Examples when data is an Array

data.map(x => x.name)Map to property

data.filter(x => x.active)Filter items

data.filter(x => x.price > 20).map(x => ({name: x.name, price: x.price}))Filter and select keys

data.reduce((a,x) => a + x.total, 0)Sum totals

data.filter(x => x.value != null).map(x => x.value).reduce((a,b) => a + b, 0)Sum field, skip nulls

[...new Set(data.map(x => x.id))]Unique IDs

[...data].sort((a,b) => a.total - b.total).slice(0,5)Top 5 by total

data.flatMap(o => o.items.map(i => ({ orderId: o.id, sku: i.sku })))Flatten nested arrays

data.flat()Flatten one level deep

data.map(x => ({...x, newKey: 'newValue'}))Add new key to each object

Object.groupBy(data, x => x.category)Group by category (ES2024+)

data.reduce((acc,x) => {(acc[x.category] = acc[x.category]||[]).push(x); return acc},{})Group by category (compatible)

Examples when data is an Object (dictionary)

Object.keys(data)List keys

Object.values(data)List values

Object.entries(data).map( ([k,v]) => ({ key: k, value: v }) )Entries to array

Object.fromEntries( Object.entries(data).map( ([k,v]) => [k.toUpperCase(), v] ) )Transform keys to uppercase

Object.fromEntries( Object.entries(data).map( ([k,v]) => [k, {...v, newKey: 'value'}] ) )Add key to all nested objects

Object.values(data.users || {}).filter(u => u.active)Filter nested users

({ count: Object.keys(data).length })Object field count

JSON.stringify(Object.entries( data.items || []).map(([k,v]) => [k, v.name, v.email] ), null, 2)Convert to table format

Notes

- Processing is local; files are never uploaded.
- In path mode, supported steps: .prop, .prop[], .prop[*], .prop[0], pipelines with |, and simple filter:/map: using x => ....