JSON sourceJSON
JSONL textJSONL
Load data and the result will appear here
JSON array → line-delimited JSON
JSON to JSONL
Array → NDJSON / JSON Lines · one record per line · stream and log friendly · runs locally
No upload, no storage
JSON is processed in memory and never sent to a server.
Share via URL fragment
Share links encode data in the # anchor — never sent to a server.
Remember last edit
Optionally keep your last input locally; clear it with one click.
Why use JSON to JSONL
One record per line
Every array item becomes an independent line you can append, tail and process one at a time.
Big-data tools eat it raw
BigQuery, Spark, jq and log pipelines take JSONL natively — no need to unwrap arrays first.
LLM dataset format
Fine-tuning datasets are typically JSON Lines; convert your array samples into the expected shape in one click.
Compact output
Each line is minified, dropping pretty-print whitespace for a smaller file.
Local · no upload
Everything runs in your browser; data is never uploaded or stored.