JSONL to JSON Converter

Convert JSONL ⇄ JSON, browse records as a table, export CSV. Handles large files and bad lines. 100% local, no tracking.

Open, convert and inspect JSON Lines files right in Chrome, with nothing uploaded. Built for anyone who works with JSONL / NDJSON: LLM fine-tuning and eval datasets, Claude Code / Codex / OpenAI session logs, application logs, BigQuery and MongoDB exports. WHAT'S NEW IN 2.0 • Opens in the side panel (or a full tab), so it no longer closes when you pick a file • Paste input: press ⌘/Ctrl+V anywhere • Both directions: JSONL → JSON array, and JSON array → JSONL • Bad lines no longer break the file: see each invalid line with its line number and error, and skip it • Table view: every record as a row, every key as a column • Export to CSV (opens correctly in Excel and Google Sheets) • Handles large files (100 MB+) smoothly; parsing runs in the background • Choose 2-space, 4-space or minified output • Light and dark theme