NDJSON to JSON

one-object-per-line → array

Combine newline-delimited JSON (NDJSON / JSONL) into a single JSON array. For richer JSONL tooling (split, slice, filter, count), use the sister site jsonlkit.com. Reverse direction at JSON → NDJSON.

Input NDJSON / JSONL

JSON array output

Paste NDJSON.

How to convert

Paste a JSON array (for → NDJSON) or NDJSON text (for → JSON array).
Output appears live. Copy or Download as .ndjson / .jsonl.
Toggle Pretty-print individual objects (off by default — NDJSON is usually one-line per record).

FAQ

What if one line is invalid?

The error message shows the line number and the parse error. Fix that line and re-run, or use json-repair on the offending line.

I have a huge NDJSON file — will the array fit in memory?

Browser memory caps usually allow ~100–500 MB before things slow. For multi-GB JSONL, use stream-oriented CLI tools like jq -s.

Will it work offline?

Yes.