100% local — your data never leaves your browser

NDJSON to JSON Converter — Free Online Tool

Convert newline-delimited JSON (JSON Lines) to a formatted JSON array, in your browser. Free and private: your data never leaves your device.

Instant Private Zero cookies
Indentation

NDJSON input

JSON output

Why convert NDJSON to JSON?

Log exports and streaming outputs arrive as one JSON record per line, which most tools and editors cannot pretty-print directly. Paste your NDJSON above to wrap it into a proper JSON array.

How it works

The converter parses each non-empty line locally as an individual JSON value and assembles them into an array, formatted with the indentation you pick (or compact). A malformed record reports its exact line number.

Frequently asked questions

Is my NDJSON data uploaded to a server?
No. Everything runs entirely in your browser with JavaScript. Nothing is sent over the network, which makes the tool safe for sensitive data.
What happens on a malformed line?
The conversion stops with an error naming the offending line number, so you can fix the exact record. Empty lines are skipped silently.

Related converters