JSONL / NDJSON Viewer & Converter
Inspect JSON Lines in a local table, locate invalid records and convert complete data to or from a JSON array without silently rounding numbers.
Enabling local controls…
1. Add your data
Tool data stays in this browser; no upload, storage or tool analytics events.
Objects, arrays and primitives are valid. Interior blank lines fail; a final newline is allowed. JSON to NDJSON requires an array.
Format and limits
UTF-8, LF / CRLF; no BOM. Input: 5 MiB, 20,000 records, 100,000 top-level cells, 500,000 total nodes and 100 levels per record. Compact JSON output is limited to 16 MiB; 5-second timeout. Duplicate keys and numbers that are unsafe or change on export are rejected; use strings to preserve them. Limits reject the complete conversion; no partial export. An empty array produces an empty JSONL file; empty JSONL has no records to inspect.
2. Preview and export
Paste data or load a sample, then convert.
How to use this tool
Paste JSONL or choose a UTF-8 file, select a direction and convert. Inspect the first 100 records, then copy or download the complete result. Any invalid line blocks export.
When not to use it
Not a streaming log service or schema validator. Quote large integers and decimals that JavaScript cannot round-trip. The table is a bounded preview, not an edited dataset.
Read the guide →