JSON / CSV Converter

Paste JSON or CSV and get the other format instantly, with nested JSON flattened into spreadsheet-ready columns.

Conversion tools

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What it helps with

  • Turn exported JSON data into a spreadsheet for Excel
  • Convert a spreadsheet CSV into JSON for a config or API
  • Flatten nested JSON into readable columns

How to use

  1. Choose the direction: JSON to CSV, or CSV to JSON.
  2. Paste the data and check the live result.
  3. Copy the output, or download the CSV in Excel-safe UTF-8 (BOM).

Examples

Customer JSON to CSV

Input

[{"name":"Tanaka","address":{"city":"Tokyo"}},{"name":"Sato","address":{"city":"Osaka"}}]

Output

name,address.city
Tanaka,Tokyo
Sato,Osaka

CSV to JSON

Input

name,age
Tanaka,30
Sato,25

Output

[{"name":"Tanaka","age":30},{"name":"Sato","age":25}]

Good to know

  • JSON input must be an array of objects, a single object, or an array of values.
  • Very deeply nested or very wide data can produce many columns.
  • Type inference converts plain numbers and true/false; values with leading zeros stay as text.

FAQ

How is nested JSON handled?
Nested objects and arrays become dot-separated columns such as user.address.city or items.0. Converting back can rebuild them into nested JSON.
Why does the CSV download open correctly in Excel?
The download is UTF-8 with a BOM, which Japanese Excel reads without mojibake. Plain UTF-8 CSV files often garble in Excel.
Is pasted data stored?
No. KoguNavi has no feature to store pasted data. Copy what you need.
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