NDJSON Converter

Convert between NDJSON (Newline Delimited JSON / JSON Lines / `.jsonl`) and standard JSON arrays (`[...]`). Formats line-delimited log streams into readable JSON arrays and flattens arrays back into NDJSON streams.

Why Use This Tool?

• Log File Analysis: Convert server log files (Datadog, Elasticsearch, AWS CloudWatch `.jsonl` logs) into JSON arrays for inspection.
• AI & Dataset Fine-Tuning: Format OpenAI, Anthropic, or HuggingFace training datasets stored in `.jsonl` format.
• Big Data Stream Export: Convert large database stream dumps between line-by-line NDJSON and standard JSON.

How to Use

1. Paste NDJSON / JSON Lines text (one JSON object per line) or JSON Array.
2. Select Mode: "NDJSON to JSON Array" or "JSON Array to NDJSON".
3. Copy converted output or download as `.jsonl` / `.json` file.

Real Working Example

Input:

NDJSON Input:
{"id":1,"name":"Alice"}
{"id":2,"name":"Bob"}

Output Result:

JSON Array Result:
[
  {
    "id": 1,
    "name": "Alice"
  },
  {
    "id": 2,
    "name": "Bob"
  }
]

Important Technical Details & Specifications

• RFC 7464 Line-Delimited Specs: Follows official RFC 7464 and jsonlines.org standards.
• Streaming Line-by-Line Parsing: Processes large log files line-by-line, skipping empty lines and tracking syntax errors by line number.
• Client-Side Engine: Fast in-browser line conversion.

Related Data & Format Tools

• Excel to JSON Converter: Convert spreadsheets to JSON.
• JSON Formatter: Prettify and validate JSON.
• JSONPath Tester: Query JSONPath expressions.