dataeng.tools

Convert JSONL to JSON — Free, Private, In-Browser

Your files never leave your browser

Convert JSONL to JSON right in your browser. JSONL is JSON Lines (NDJSON) — one JSON object per line, ideal for streaming and append-only logs; JSON is a single JSON array of records — ubiquitous in APIs and easy to eyeball. This tool reads your JSONL file with DuckDB-WASM and writes JSONlocally — your data never leaves your machine, and there’s no upload, account, or size cap beyond your browser’s memory.

Drop a JSONL file below to preview its schema and download it as JSON. Because everything runs client-side, it works offline and keeps even sensitive data private.

Drop a file or click to browse

Drop a JSONL file — processed locally, never uploaded

Frequently asked questions

Is my file uploaded anywhere?
No. The JSONL→JSON 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.

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