Convert CSV to JSONL — Free, Private, In-Browser
Your files never leave your browserConvert CSV to JSONL right in your browser. CSV is comma-separated text — the universal, human-readable format every tool can open; JSONL is JSON Lines (NDJSON) — one JSON object per line, ideal for streaming and append-only logs. This tool reads your CSV file with DuckDB-WASM and writes JSONLlocally — your data never leaves your machine, and there’s no upload, account, or size cap beyond your browser’s memory.
Drop a CSV file below to preview its schema and download it as JSONL. Because everything runs client-side, it works offline and keeps even sensitive data private.
Drop a file or click to browse
Drop a CSV file — processed locally, never uploaded
Frequently asked questions
- Is my file uploaded anywhere?
- No. The CSV→JSONL conversion runs entirely in your browser via DuckDB-WASM. Your file never leaves your device.
- How large a file can I convert?
- It's bounded by your browser's available memory rather than any server limit — files in the hundreds of MB are routine. DuckDB runs single-threaded here, so very large files just take a little longer.
- Do I need an account?
- No — it's free and requires no sign-up.