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JSON to CSV Converter

Convert JSON to CSV instantly in your browser – flatten nested objects, handle arrays, choose delimiters, and export Excel-ready files with zero uploads.

Updated

What is the JSON to CSV Converter?

Convert JSON to CSV in seconds — no uploads, no signup, no server. Paste an API response, MongoDB export, or nested JSON file and get a clean, Excel-ready CSV instantly.

Unlike basic online converters that struggle with large files, send your data to the cloud, or turn arrays into unreadable ["red","blue"] strings, this tool runs 100% in your browser. Your data never leaves your device.

It handles the real-world messiness of JSON:

  • Nested objects are flattened automatically with dot notation (user.address.city)
  • Arrays can be kept as JSON, joined with a custom separator, or exploded into separate rows
  • JSON Lines (NDJSON) is detected automatically
  • Inconsistent keys across objects become proper columns with empty cells where needed

Built for developers, data analysts, and spreadsheet users who need to convert JSON to CSV for Excel, Google Sheets, or data pipelines. Choose your delimiter (comma, semicolon, tab, pipe), control quoting, and preview results live with row/column stats and warnings for Excel's 1,048,576 row limit.

Fast, private, and free — the JSON to CSV converter that actually understands your data.

How it works

  1. Paste your JSON in the left editor. It accepts:
  • An array of objects: [{"name":"Alice"}, {"name":"Bob"}]
  • A single object: {"name":"Alice"}
  • JSON Lines: one valid JSON object per line
  1. Conversion happens instantly. The tool:
  • Parses and validates your JSON
  • Flattens nested objects if enabled
  • Collects all unique keys across records to build headers
  • Applies your array handling choice
  1. Adjust options as needed:
  • Delimiter: comma for US, semicolon for Europe, tab for TSV
  • Flatten separator: dot (.), underscore (_), or slash (/)
  • Array mode:
    • Stringify: keeps arrays as JSON text (safest)
    • Join: combines values like "red, blue"
    • Explode: creates a new CSV row for each array item
  • Include headers, quote all, null handling

  1. Review the preview table and stats. Warnings appear for deep nesting, sparse data, or very wide outputs.

  2. Copy or download your CSV. Open directly in Excel, Sheets, or any database importer.

Under the hood

  • Flattening uses recursive dot-notation up to 10 levels deep to avoid runaway columns
  • CSV output follows RFC 4180 with proper escaping of quotes, commas, and newlines
  • All processing uses the File API and Web Workers-compatible logic — no data is sent to a server

Examples

Simple user list

Convert a flat JSON array of users to CSV for Excel or Google Sheets

[{"name":"Alice","age":30,"city":"NYC"},{"name":"Bob","age":25,"city":"LA"}]
 
name,age,city
Alice,30,NYC
Bob,25,LA

Flatten nested JSON

Automatically flatten nested objects using dot notation to preserve structure

[{"id":1,"user":{"name":"John","email":"john@example.com"},"address":{"city":"Boston"}},{"id":2,"user":{"name":"Jane","email":"jane@example.com"},"address":{"city":"Seattle"}}]
 
address.city,id,user.email,user.name
Boston,1,john@example.com,John
Seattle,2,jane@example.com,Jane

Explode arrays into rows

Turn nested arrays into multiple CSV rows using explode mode for order data

[{"order_id":1001,"items":["A1","B2"]},{"order_id":1002,"items":["C3"]}]
 
items,order_id
A1,1001
B2,1001
C3,1002

Frequently asked questions

How do I convert JSON to CSV?

Paste your JSON into the input box. If it's a valid array of objects, you'll see CSV output instantly on the right. Click "Download CSV" or "Copy CSV" to use it in Excel or Google Sheets. No account needed.

How do you handle nested JSON objects?

We flatten them by default using dot notation. { "user": { "name": "John", "address": { "city": "NYC" } } } becomes columns user.name and user.address.city. You can change the separator to underscore or slash, or turn flattening off to keep nested objects as JSON strings.

What happens to arrays inside my JSON?

You have three choices. Stringify keeps the array as ["a","b"] text in one cell — this is what most converters do. Join combines values into "a, b". Explode creates a new CSV row for each array element, which is ideal for order line items or tags and is a feature most free tools lack.

Is my data secure? Do you upload files?

No. Everything runs locally in your browser using JavaScript. Your JSON is never sent to a server, stored, or logged. This is the same privacy model as konklone.io/json and csvjson.com, but with more features.

Can I convert JSON Lines (NDJSON) files?

Yes. If you paste multiple lines where each line is a valid JSON object, the tool auto-detects NDJSON format and converts all lines into one CSV table. This is perfect for logs and streaming API exports.

Why does CSV lose numbers and booleans?

CSV is a text-only format. All values become strings — numbers like 123 become "123", booleans become "true"/"false", and nulls become empty cells. Excel may auto-convert them back when you open the file, but the CSV itself cannot preserve JSON data types.

What is the difference between stringify, join, and explode?

Stringify is safest for complex data but leaves JSON in cells. Join is readable for simple string arrays. Explode is best for analysis because it turns one JSON record with 5 items into 5 CSV rows, preserving relationships without nested text.

Can I use a semicolon or tab delimiter for Excel Europe?

Yes. Select "Semicolon (;)" for European Excel or "Tab" for TSV files. The tool properly quotes fields containing your chosen delimiter, so commas inside text won't break your columns.

Why am I getting warnings about sparse data or too many columns?

That happens when your JSON objects have different keys, or are nested very deeply. The converter creates a column for every unique key it finds, leaving empty cells where a record lacks that field. If you see "very wide output," consider pre-filtering your JSON or turning off flattening for deeply nested branches.

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