JSON to CSV Converter

JSON is great for nested, flexible data, but spreadsheets, BI tools and many import screens only understand flat tables. This converter walks through every JSON object, turns nested properties into columns, collects every key that appears in any record, and writes a standards-compliant CSV file.

1. Paste JSON or drop a .json file — an array of objects, an API response or a single object.
2. Keep Flatten nested JSON to columns enabled to turn nested objects into parent.child columns.
3. Choose a comma or semicolon under CSV output.
4. Copy the CSV or download it; the downloaded file opens correctly in Excel, accents included.

Example

[
  { "id": 1, "name": "Jane", "address": { "city": "Boston", "zip": "02134" }, "tags": ["admin", "beta"] },
  { "id": 2, "name": "Omar, Jr.", "address": { "city": "Casablanca" }, "phone": "+212 600-000000" }
]

id,name,address.city,address.zip,tags,phone
1,Jane,Boston,02134,"[""admin"",""beta""]",
2,"Omar, Jr.",Casablanca,,,+212 600-000000

The nested address becomes address.city and address.zip, the array is kept as JSON text in one cell, phone appears only on the second record but still gets its own column, and the comma in Omar, Jr. is quoted so it does not create an extra column.

How nested JSON is flattened

Each nested object adds its key as a prefix, joined with a dot: {"a":{"b":{"c":1}}} becomes a column named a.b.c. Arrays are written as JSON text in a single cell, which preserves every element and keeps the number of columns predictable. If you prefer each nested object as raw JSON in one cell, untick Flatten nested JSON.

Records with different keys

Real-world JSON is rarely uniform. The converter scans every record and builds the column list from all keys, in the order they first appear. A record that lacks a key simply gets an empty cell, so you never lose fields that only exist on some records — a common failure of tools that look only at the first object.

Accepted JSON structures

• Array of objects: one row per object.
• API-style wrapper like {"data":[…]} or {"results":[…]}: the inner array is detected and used.
• Single object: one row.
• Array of values: one column called value.

Quoting rules

Values that contain the delimiter, a double quote, a line break, or leading/trailing spaces are wrapped in double quotes, and quotes inside them are doubled — exactly what RFC 4180 specifies and what Excel, Google Sheets, pandas and databases expect. Other values are left unquoted to keep the file compact and readable.

Convert JSON to CSV in code

For one-off files the tool above is quickest. To automate the same task in a script or pipeline, these snippets are a good starting point.

Python (pandas)

import json
import pandas as pd

with open("data.json", encoding="utf-8") as f:
    data = json.load(f)

pd.json_normalize(data).to_csv("data.csv", index=False, encoding="utf-8-sig")

Command line (jq)

# Flat JSON arrays only; nested values must be flattened first
jq -r '(.[0] | keys_unsorted) as $k | $k, (.[] | [.[$k[]]]) | @csv' data.json > data.csv

Frequently asked questions

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