JSON Lines Converter
Convert JSONL or NDJSON to a JSON array and back. Keep large integers and report invalid source lines.
How to use
JSON Lines stores one complete JSON value per line. Paste log exports or data records to wrap them in an array. Reverse mode requires an array and writes each item as one compact line.
Numeric tokens stay unchanged, including 9007199254740993, 2.370 and 1e500. Values can be objects, arrays, strings, numbers, booleans or null. Blank lines are skipped only when the option is enabled; one final line ending is allowed.
Behavior and limits
Invalid input reports its one-based source line. Literal line breaks inside JSON strings must be escaped as \n. Limit: 200,000 characters and 10,000 source lines. This is not a streaming multi-gigabyte log viewer.
Questions & answers
Can JSONL contain an array on one line?
Yes. Each line can be any valid JSON value. It becomes one item in the outer result array.
Can I use this without uploading data?
Processing runs on your device. Input is not sent to a conversion API. Keep the page open until the result is ready.