JSON Lines Converter
Convert JSON Lines (NDJSON) to a JSON array and back
About
Convert between JSON Lines (NDJSON — one JSON value per line) and a JSON array in either direction. Common for log streams, LLM training data, and ndjson-based APIs. Per-line parsing errors are reported with the line number. Everything runs in your browser; nothing is uploaded.
About this tool
Convert JSON Lines (NDJSON) to a JSON array, or JSON back to NDJSON. Per-line error reporting. Free, client-side, no signup. JSON Lines Converter runs in the browser on DevTools. There is no signup, and your input stays on this device unless the tool explicitly performs a live network lookup.
What this tool does not do
- JSON Lines Converter is a free in-browser utility, not a hosted API. It does not keep server-side history and is not a substitute for production verification in your own stack.
How do I use this tool?
How do I use JSON Lines Converter?
Open JSON Lines Converter, enter or paste your input, and copy the result. The page works without an account.
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