Free online JSON Lines (NDJSON) to JSON converter. Parse newline-delimited JSON into a single JSON array. Reports parse errors per line. Runs locally in your browser.
100% Local
How to Use the JSON Lines to JSON
Paste NDJSON (one JSON object per line) into the input box. Click Convert to JSON and the lines are parsed into a single JSON array. Use Clear to reset.
How lines are processed
Each non-empty line is parsed as an independent JSON value
All successfully parsed values are collected into a single array
Lines that fail to parse are reported with their line number
Empty lines are silently skipped
Features
Per-line error reporting — shows which lines failed
Handles large NDJSON streams with thousands of lines
Reversible with the JSON to NDJSON tool
All processing runs locally in your browser. Your data is not uploaded to any server.