Convert JSON Lines to CSV, free in your browser

Convert JSONL or NDJSON files containing one flat object per line into CSV. Columns are the union of keys, in first-seen order.

How to convert JSON Lines to CSV

1. Choose a JSONL or NDJSON file.
2. Convert and review the CSV preview.
3. Download the CSV file.

Limits & good to know

• JSONL and NDJSON files up to 50 MB are processed on your device.
• Each non-empty line must be a flat JSON object; invalid lines report their line number.
• Nested arrays and objects are not flattened.

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.

What if records have different keys?

The output includes every key found across all records. A record gets a blank cell where it does not contain a key.

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.