format · validate · convert · runs locally

NDJSON to JSON

Paste NDJSON / JSON Lines (JSONL) — one JSON value per line — and get a single JSON array. Blank lines are ignored, and a bad line is reported by its line number. Copy it or download the .json. Runs in your browser.

Frequently asked questions

What are NDJSON, JSONL, and JSON Lines?

They are the same format: newline-delimited JSON, with one complete JSON value on each line. Log pipelines, LLM datasets, and streaming APIs use it heavily.

What if one line is invalid?

Conversion stops and reports the offending line number and error so you can fix that single record.