File Converter

CSV to NDJSON converter Free, private, no upload.

Convert CSV files to NDJSON right in your browser. NDJSON streams line by line, which is what log tools, BigQuery, Elasticsearch and data pipelines expect. Your files are never uploaded.

or drop files anywhere · paste with Ctrl/⌘ + V

How to convert CSV to NDJSON

  1. 1 Drop your CSV files onto the page, or click “Choose files”. You can add many at once, or a whole folder.
  2. 2 NDJSON is already selected as the output. Optionally open Options to adjust sort keys.
  3. 3 Click Convert, then Save. Converting several files? Save them all as one ZIP.

About the formats

CSV · Comma-separated values

CSV is a simple table format: one row per line, columns separated by commas. Every spreadsheet and database can import it.

NDJSON · Newline-delimited JSON

NDJSON (also called JSON Lines) stores one JSON object per line. It is used for logs, data pipelines and bulk imports.

The conversion runs on your device using proper parsers for each format (yaml, smol-toml, fast-xml-parser and PapaParse). You can adjust: sort keys.

Frequently asked questions

How do I convert CSV to NDJSON?

Drop your CSV files onto the page, or click “Choose files”. You can add many at once, or a whole folder. NDJSON is already selected as the output. Optionally open Options to adjust sort keys. Click Convert, then Save. Converting several files? Save them all as one ZIP.

Are my files uploaded to a server?

No. The conversion runs entirely in your browser using WebAssembly. Your files never leave your device, so it is safe for private photos, contracts and business data. Once the page has loaded it even works offline.

Will converting CSV to NDJSON reduce quality?

No. CSV to NDJSON conversion is exact: the data is parsed and rewritten, not approximated.

Can I convert multiple CSV files to NDJSON at once?

Yes. Add as many CSV files as you like; they are converted in parallel on your device and you can download them all as a single ZIP.

Is it free? Are there limits?

It is free, with no sign-up, no watermark and no daily limits. Because nothing is uploaded there is no upload size limit either; the only limit is your device’s memory, which matters mostly for very large videos.

See everything the CSV converter and the NDJSON converter can do.