JSONL ⇄ Excel Converter
Turn a JSONL file into an Excel spreadsheet, or export a workbook back to JSON Lines. Supports files up to 200MB (Excel output is limited to 1,048,576 rows per the .xlsx format spec — convert to CSV or JSON instead for unlimited rows) — everything runs entirely in your browser.
Or convert a .jsonl file directly — supports files up to 200MB
Drag & drop a file here, or click to browse
Processed in the background, so the page stays responsive even for huge files
How to use this tool
Paste JSONL (one JSON object per line) and click convert to download an Excel spreadsheet with one row per line. Switch to Excel → JSONL to upload a workbook and export each row as a compact JSON object, one per line — a common format for log ingestion and LLM fine-tuning datasets. Files up to 200MB are supported — large uploads are processed in a background Web Worker so the page never freezes, and processing happens locally in your browser.
Frequently Asked Questions
Is there a file size limit?
Yes — files up to 200MB are supported. Conversion runs in a background Web Worker, so even large files process smoothly without freezing your browser tab. Files over 200MB are rejected immediately with a clear message. Excel output specifically is capped at 1,048,576 rows (a limit of the .xlsx format itself, not something we control) — convert to CSV or JSON instead if you need more rows than that.
Is my data uploaded anywhere?
No. Every conversion happens locally in your browser, including for large files — nothing is ever sent to a server.
What does Excel → JSONL convert?
It reads the first sheet of the uploaded workbook and writes each row out as a compact JSON object, one per line.
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