JSON to JSONL

JSON Lines, also NDJSON, writes exactly one JSON value per line and is the preferred format for logs, streaming pipelines, database imports and machine-learning training data. A classic JSON array, by contrast, requires reading the whole file at once. This tool takes your JSON array and writes each entry as its own compact line.

The conversion runs entirely locally in your browser, in pure JavaScript. From an array of objects or values you get one compact JSON per line; the order is preserved. An object that wraps such an array (for example under the data key) is also recognised and its array is used. The result can be streamed line by line, processed with tools like jq, or loaded into a database in chunks.

This closes the round-trip: JSONL to JSON and now JSON to JSONL are both available locally. It stays honest about it: an array is expected at the root; a single object without a wrapping array or a scalar is rejected with a clear message instead of producing a misleading result. Nothing is uploaded.

Specifications

In 3 steps

1. Drop or pick your JSON file.
2. The tool writes each entry as its own line.
3. Download the JSONL file.

Limitations: Expects a JSON array at the root (or an object that wraps exactly one such array). Each entry is written as one compact JSON line, the order is preserved. A scalar or an object without a wrapping array is rejected with a clear message. Nested structures within an entry are kept as compact JSON on the line.

FAQ

Related tools

• JSONL to JSON
• JSON to CSV
• CSV to JSON