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Nablyx

Free JSON to CSV converter

Nothing uploadedTested up to 150 MB

Convert nested JSON objects into a practical CSV with flattened paths, selectable columns, array handling, and delimiter options.

Convert one nested JSON file entirely in your browser without uploading it, up to 150 MB, and download a new CSV. Nested object paths become dot-separated column names such as profile.name. Fields discovered in any record become CSV columns, so when records have different keys the missing cells are left empty. For arrays, you can keep simple list values together in one cell, preserve an array as JSON, or expand list items into extra rows; expanded sibling lists are matched by position rather than multiplied together. It handles one file at a time. A file near the cap can take tens of seconds, with visible progress and a Cancel control while it runs. The practical limit is not bytes alone: very irregular JSON where almost every record introduces new fields can create too many distinct flattened column names and be refused safely even when the file is well under the size cap.

Processed locally in your browser

JSON conversion workspace

Flatten nested objects, choose columns, and control arrays and delimiters.

Results will appear here

Add valid data in the workspace above to preview and download the result.

Turn structured JSON into a usable table

  1. 1

    Upload a JSON object or array of objects.

  2. 2

    Review automatically flattened nested fields.

  3. 3

    Choose which columns to export.

  4. 4

    Choose whether list values stay together in one cell or expand into extra rows, then check the resulting row count.

  5. 5

    If values such as 00123 are IDs, postal codes, SKUs, or phone numbers, preserve numeric-looking text so leading zeros survive.

  6. 6

    Before downloading, preview names, dates, IDs, empty fields, selected columns, and the final row count.

Built for the real task

  • Nested object flattening
  • Array handling
  • Column selection
  • Comma, semicolon, or tab output

See the transformation

Nested JSON becomes a readable flat table.

Nested JSON is turned into clear columns so the data is easy to read and reuse.

JSON
{
  "id": 1042,
  "name": "Alex",
  "address": { "city": "Berlin" }
}
Result
idnameaddress.city
1042AlexBerlin

Browser limits

Files are limited to 150 MB to protect browser stability, especially on phones. Processing stays on this device.

Nested object flattening

Convert nested JSON objects into a practical CSV with flattened paths, selectable columns, array handling, and delimiter options.

Private by design

The selected file is not uploaded to Nablyx.

Processed locally in your browser

No. This tool reads and transforms the file locally in your browser.

Common uses

  • Nested object flattening
  • Array handling
  • Column selection
  • Comma, semicolon, or tab output

What should I check before downloading the CSV?

Confirm that the selected columns are the ones you need, review the preview after choosing how lists are handled, and check important IDs before continuing. Expanding list items can create more CSV rows than source records, and spreadsheet apps may reformat dates or number-like text after opening the file, so preserve numeric-looking text when leading zeros matter.

Related guide

How to Convert Nested JSON to CSV Correctly

Related tools

Continue with a related Nablyx tool.

Ready to work on your file?

Return to the workspace and process it locally.

Convert JSON to CSV