Paste newline-delimited JSON — one JSON value per line, the format used by log streams, ML training exports, and bulk API dumps — and see every line validated independently, with per-line error messages for anything malformed. Filter to valid-only or invalid-only, search across raw text, and export either the clean subset or everything back out as .jsonl. Virtualized rendering stays smooth even past 100,000 records. 🔒 100% local-first — nothing you paste ever leaves your browser.