JSONL Converter

How to Use

1. Paste JSONL / NDJSON into the left panel, or open a local .jsonl, .ndjson, .json, or .txt file.
2. Click Validate to check each line and see exact line numbers for parse errors.
3. Click JSONL → JSON to build a JSON array from the valid records.
4. Paste a JSON array into the right panel and click JSON → JSONL to create compact JSON Lines output.
5. Use Download .json or Download .jsonl to save the converted result.

Worked Example

Input JSONL:

{"id":1,"event":"signup","user":"alice"}
{"id":2,"event":"purchase","user":"bob","amount":29.99}

Output JSON array:

[
  {
    "id": 1,
    "event": "signup",
    "user": "alice"
  },
  {
    "id": 2,
    "event": "purchase",
    "user": "bob",
    "amount": 29.99
  }
]

JSONL vs JSON Arrays

A JSON array wraps every record inside one large document. JSONL writes each record as a standalone JSON value on its own line. That line-oriented shape works well for logs, streaming exports, command-line processing, and large datasets where each record can be handled independently.

Validation Details

The validator parses every non-empty line with JSON.parse(). Successful lines are counted as valid records. Failed lines appear in the issue panel with the line number, parser message, and a short preview of the original line.