Convert CSV to JSON Lines, free in your browser

Convert every CSV or TSV data row into one JSON object on its own line (JSONL/NDJSON), ready for streaming tools and data pipelines.

How to convert CSV to JSON Lines

1. Choose a CSV or TSV file.
2. Choose whether the first row contains column names.
3. Convert and download the JSON Lines file.

Limits & good to know

• CSV and TSV files up to 50 MB are processed on your device.
• Values remain text to preserve identifiers and leading zeros.
• Duplicate column names are made unique by adding a numeric suffix.

Frequently asked questions

Are my files uploaded to a server?

Your files are processed on your device, not uploaded to our servers. Your file and edits are saved in this browser for recovery, and previous documents remain in Saved drafts when you open another file. Use Saved drafts to resume or delete individual copies, or clear this site’s browser data to remove all copies. Browser storage can be cleared or become unavailable; download important work.

How is JSON Lines different from a JSON array?

JSON Lines stores one complete JSON value per line without wrapping the records in an array. This makes it convenient for line-by-line and streaming processing.

Is this really free, or free "until you hit a limit"?

Really free. Unlike most "free" PDF sites there is no task-per-day cap, no locked Pro features, no watermark stamped on your file, and no payment step before download. Every tool is the full tool.