NDJSON to JSON

Turn newline-delimited JSON (NDJSON, also called JSON Lines) into one JSON array. Paste the lines, wrap them in an array, and explore the result as a tree. Nothing is uploaded.

Add to Chrome Free: formats JSON pages right in the tab.

How to convert NDJSON to a JSON array

Paste the NDJSON into the editor above, or drop a .ndjson or .jsonl file onto it.
The editor reports how many top-level values it found. Press Wrap in array.
The values become one formatted array. Explore it in the Viewer tab, copy it or save it as a .json file.

What it handles

Any JSON values

Lines can hold objects, arrays, strings or numbers. Each one becomes an item of the array, in the original order.
Flexible separators

Values separated by new lines, spaces or commas are all recognized, as are JSON text sequences that start each value with a record separator.
Errors with a location

If one line is broken, the editor shows the error with its line and column, so you can fix it before wrapping.

More JSON tools

Frequently asked questions

What is NDJSON?

Newline-delimited JSON stores one JSON value per line. Logs, data exports and streaming APIs use it because each line can be written and read on its own. It is also known as JSON Lines.

Why not just paste NDJSON into a JSON tool?

A JSON document may hold only one top-level value, so many tools reject NDJSON or keep only the first value. This one counts the values and keeps all of them.

Is there a size limit?

Files up to about 10 MB work smoothly, and wrapping runs in a background worker.