8 Free JSON to CSV Converters

JSON is how APIs, apps and databases hand you data. CSV is how spreadsheets, CRMs and most reporting tools want to receive it. Sooner or later, anyone who exports a product feed, pulls analytics from an API or downloads records from a web app ends up with a JSON file and a spreadsheet that refuses to open it.

A free JSON to CSV converter bridges that gap in seconds. The catch is that JSON rarely arrives flat. Customer records carry nested addresses, orders carry lists of items, and every converter treats those nested fields differently. Some flatten them into extra columns, some cram them into one cell, and some drop them.

I picked eight free tools that convert JSON to CSV: five online converters that work in the browser and three command line tools for bigger files. To compare them on equal terms, I ran the same 100,000 record nested JSON file through the command line tools and timed each one. Below you get what each tool does well, where it falls short, and which one fits your file.

What a JSON to CSV Converter Does With Your Data

A JSON to CSV converter reads a list of objects and turns each object into a row and each key into a column header. Flat data converts cleanly. Nested data is where tools differ. Here are three sample records with a nested address object and a tags array:

[
 {
  "id": 0,
  "name": "Customer 0",
  "email": "user0@example.com",
  "plan": "pro",
  "address": {
   "city": "Pune",
   "zip": "10000"
  },
  "orders": 25,
  "tags": [
   "vip",
   "beta"
  ]
 },
 {
  "id": 1,
  "name": "Customer 1",
  "email": "user1@example.com",
  "plan": "team",
  "address": {
   "city": "Pune",
   "zip": "10001"
  },
  "orders": 23,
  "tags": [
   "vip",
   "churn-risk"
  ]
 },
 {
  "id": 2,
  "name": "Customer 2",
  "email": "user2@example.com",
  "plan": "free",
  "address": {
   "city": "Pune",
   "zip": "10002"
  },
  "orders": 5,
  "tags": [
   "beta",
   "new"
  ]
 }
]

A good converter turns address.city and address.zip into their own columns and handles the tags list in a predictable way. Keep this sample in mind; the test section shows exactly how each command line tool treated it.

Free Online JSON to CSV Converters

These five run in a web browser with zero install. They fit one off conversions and files up to a few megabytes.

1. ConvertCSV: Free JSON to CSV Converter With File, Paste and URL Input

Website	convertcsv.com
Input	Paste, upload a file, or load from a URL
Delimiters	Comma, semicolon, colon, bar, tab or a custom character
Extras	Header row toggle, forced quotes, date formatting, CRLF or LF line endings
Price	Free

ConvertCSV gives you the most control of any free online JSON to CSV tool. Paste JSON, upload a file or point it at a URL, then choose the delimiter, quoting rules, line endings and even the date format before saving the file. If your JSON sits inside a variable, you name the array to convert. It expects an array of objects, so trim deeply nested API responses down to the main array first.

2. Konklone JSON: Open Source JSON to CSV Tool That Flattens Nested Data

Website	konklone.io/json
Processing	Entirely in your browser, with zero server upload
Nested data	Finds the main array and flattens each row recursively
Licence	Open source, public domain code on GitHub
Price	Free

Eric Mill built this converter to make JSON as easy to open as a spreadsheet, and it still does that job well. It looks for the array that holds your records, then flattens nested objects into separate columns using logic adapted from the csvkit project. Because it runs as a static page, your data stays on your machine, which matters for customer exports. It handles most common shapes, though unusual structures need cleanup first.

3. TableConvert: Convert JSON to CSV and Edit the Table Before Download

Website	tableconvert.com
Formats	30+ including CSV, Excel, Markdown, HTML, SQL, XML and YAML
Editor	Spreadsheet style editor with search and replace
Processing	In the browser, with zero server storage
Price	Free

TableConvert is the JSON to CSV tool to use when the data needs a tidy up before export. After the conversion, the table opens in an editor where you rename columns, delete rows and run search and replace. The same page also exports to Excel, Markdown or SQL, handy when the CSV is only one stop on the way to a report or a database.

4. OnlineTools: Browser Based JSON to CSV Conversion With Custom Delimiters

Website	onlinetools.com
Processing	JavaScript in your browser; data stays local
Options	Header row, separator, quote character, always quote fields
Free plan	Personal use, daily limit, download timer and ads
Premium	Removes limits and allows commercial use

OnlineTools keeps things simple: paste JSON, pick a separator and quote character, and copy the CSV. Switching the separator to a semicolon or pipe gives you SSV or PSV files for systems that choke on commas. The free tier is for personal use with a daily cap, so teams converting files every day will want the paid plan or a command line tool.

5. ExtendsClass: JSON to CSV, TSV and Excel Converter

Website	extendsclass.com
Input	Drag and drop a file or paste text
Output	CSV, TSV or Excel download, or copy to clipboard
Reverse	Also converts CSV or TSV back to JSON
Price	Free

ExtendsClass is the quickest route from JSON straight to an Excel file. Drop the file in, the output appears as soon as the JSON validates, and you download CSV, TSV or XLSX. It also works the other way, turning a CSV back into JSON, which helps when you edit data in a spreadsheet and need to push it back to an API.

Free Command Line Tools to Convert JSON to CSV

Online converters slow down or freeze on large files. For anything over a few megabytes, or for conversions you repeat every day, these three free tools do the job from a terminal or a script.

6. jq: The Fastest Free JSON to CSV Converter in My Test

Website	jqlang.org
Platforms	Linux, macOS, Windows
Nested data	You choose exactly which fields become columns
Test result	100,000 records in 1.80 seconds
Price	Free, open source

jq is the standard command line JSON processor, and its @csv filter writes proper CSV. You map each nested field to a column yourself, which takes a minute to write and gives you total control over the output. This command flattens the address and joins the tags with semicolons:

jq -r '(.[0]|del(.address,.tags)|keys_unsorted) as $k
  | ($k + ["address_city","address_zip","tags"]),
    (.[] | [.[$k[]]] + [.address.city, .address.zip, (.tags|join(";"))])
  | @csv' customers.json > customers.csv

7. pandas json_normalize: Convert Nested JSON to CSV in Python

Website	pandas.pydata.org
Platforms	Anywhere Python runs
Nested data	Flattens nested objects into dotted columns automatically
Test result	100,000 records in 2.15 seconds
Price	Free, open source

If you already work in Python, three lines convert nested JSON to CSV. json_normalize spreads nested objects into columns such as address.city. Lists stay inside one cell as text, so explode or join them first if each tag needs its own column.

import json
import pandas as pd

data = json.load(open("customers.json"))
pd.json_normalize(data).to_csv("customers.csv", index=False)

8. Miller: One Command JSON to CSV Converter That Flattens Arrays

Website	miller.readthedocs.io
Platforms	Linux, macOS, Windows single binary
Nested data	Flattens objects and arrays into numbered columns automatically
Test result	100,000 records in 3.43 seconds
Price	Free, open source

Miller is the easiest command line JSON to CSV converter to learn. One command handles nested objects and arrays with zero setup, turning tags into tags.1 and tags.2 columns. It ran slowest in my test, though 3.4 seconds for 100,000 records is still quick for daily work.

mlr --ijson --ocsv cat customers.json > customers.csv

How Fast Is Each Free JSON to CSV Converter? My 100,000 Record Test

I generated a 17.8 MB JSON file with 100,000 customer records, each with a nested address object and a two item tags array, then converted it with each command line tool on the same Linux machine and averaged repeated runs.

How Each Tool Converted the Nested Fields

Tool	Address Object	Tags Array	Setup Needed
jq	Columns you name (address_city, address_zip)	Joined into one cell as vip;beta	Write a field map
pandas json_normalize	Automatic columns (address.city, address.zip)	Kept as a Python list in one cell	Three lines of Python
Miller	Automatic columns (address.city, address.zip)	Split into tags.1 and tags.2	One command

Speed is only part of the picture. Miller produced the cleanest spreadsheet with zero thought, pandas needs one extra step for lists, and jq gives the tidiest output once you write the mapping. For a 17.8 MB file, all three finish faster than opening a browser tab and pasting the data.

Free JSON to CSV Converters Compared

Free JSON to CSV Converters at a Glance

Tool	Type	Data Stays on Your Machine	Handles Nested JSON	Best For
ConvertCSV	Online	Unconfirmed	Array of objects	Delimiter and format control
Konklone JSON	Online, open source	Yes	Flattens recursively	Private one off conversions
TableConvert	Online	Yes	Flattens to columns	Editing data before export
OnlineTools	Online	Yes	Basic	Quick pastes with custom separators
ExtendsClass	Online	Unconfirmed	Array of objects	Direct Excel export
jq	Command line	Yes	You map fields	Speed and exact output
pandas	Python library	Yes	Automatic objects	Python workflows
Miller	Command line	Yes	Automatic objects and arrays	Easiest bulk conversion

Which Free JSON to CSV Converter Should You Use?

• A small file, once: Konklone JSON or TableConvert, both in the browser and both keep data local.
• Odd delimiters or date formats: ConvertCSV.
• Straight to Excel: ExtendsClass.
• Big files or daily jobs: Miller for zero setup, jq for speed and control.
• Inside a data pipeline: pandas.

If the JSON comes from scraping, our comparison of Browse AI vs Octoparse covers tools that export CSV directly, and our webhook testing tools help when the JSON arrives through an API callback.

Tips to Convert JSON to CSV and Keep Every Field

• Check the root. Most converters expect an array of objects. If your records sit under a key such as data or results, point the tool at that array.
• Decide how to handle lists. Join them into one cell, split them into numbered columns, or explode them into extra rows, and stay consistent.
• Watch for missing keys. Records with extra fields add columns; spot check the header row against your source.
• Mind leading zeros. Zip codes and IDs lose leading zeros when Excel opens a CSV; import the column as text.
• Keep sensitive data local. For customer records, use a browser based or command line tool so the file stays on your computer.

Free JSON to CSV Converter FAQs

What Is the Best Free JSON to CSV Converter Online?

Konklone JSON for privacy and nested data, TableConvert for editing the table before export, and ConvertCSV for the most output options.

How Do I Convert Nested JSON to CSV for Free?

Use a converter that flattens nested objects, such as Konklone JSON or TableConvert online, or Miller and pandas json_normalize offline. Each turns nested keys like address.city into their own columns.

Is It Safe to Convert JSON to CSV Online?

Tools that run in the browser, such as Konklone JSON, TableConvert and OnlineTools, keep your data on your device. For confidential files, a command line tool is the safest choice.

How Do I Convert a Large JSON File to CSV?

Use a command line tool. In my test, jq converted a 17.8 MB file with 100,000 records in 1.80 seconds, pandas in 2.15 seconds and Miller in 3.43 seconds.

Does Excel Convert JSON to CSV?

Excel imports JSON through Get Data and Power Query, and you then save the sheet as CSV. It works for small files and needs a paid Excel licence.

How Do I Convert CSV Back to JSON?

ExtendsClass, TableConvert and ConvertCSV convert CSV to JSON as well, and Miller does it with mlr –icsv –ojson.

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