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NDJSON to CSV

Flatten newline-delimited JSON records into a spreadsheet-ready CSV file. Process locally in your browser with HappyCSV.

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How to use this tool

Quick start

Built for turning jsonl logs or api records into a flat spreadsheet.

Everything runs in your browser, so you can test the workflow with sample data when available before using production files.

Output: A CSV with one row per JSON record.

  1. 1Upload an NDJSON or JSONL file.
  2. 2Review flattened nested fields.
  3. 3Download the CSV or fix the reported line if parsing fails.

How to NDJSON to CSV

  1. 1Upload an NDJSON or JSONL file.
  2. 2Review flattened nested fields.
  3. 3Download the CSV or fix the reported line if parsing fails.

Why Use This Tool?

  • ✓Flatten newline-delimited JSON records into a spreadsheet-ready CSV file.
  • ✓A CSV with one row per JSON record.
  • ✓Files are processed locally in this browser.
  • ✓Keep the source file and review the result before importing it elsewhere.

Frequently Asked Questions

What does this tool support?

A CSV with one row per JSON record.

What are the processing limits?

Up to 100 MB per CSV, 20 MB per complex document; 250,000 rows, 1,000 columns, 2 million cells, and 128 MB output. Jobs stop after two minutes. Large files may need splitting.

Are my files uploaded?

No. File processing stays in your browser. Files are not automatically saved for the next visit.

Can I process multiple files?

This tool processes one file at a time.