LazySheet is a fast, free desktop viewer for Excel, CSV and TSV files. Open huge sheets instantly with zero latency on macOS, Windows and Linux.
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Hunter
📌
Hey Product Hunt! 👋
My actual workflow: I get a lot of CSV/Excel files (many from college), and I want to analyze them with ChatGPT/Claude. Two things always annoyed me:
1. I want to control exactly which rows/columns I hand to the AI — not upload the whole file blindly.
2. I just want a quick sum of some numbers without writing =SUM() first.
So I made LazySheet, a fast, local-first desktop viewer for spreadsheets. Local-first means your files never leave your machine — no upload, no cloud, no account, no telemetry. It even works fully offline. The only thing that ever leaves your computer is the exact range you choose to copy into the AI. That's the whole point: you decide what the model sees.
The features I actually use:
- Copy as Markdown — select a range, copy, paste into the AI. Clean table, model reads it perfectly.
- Instant aggregates — select cells, the sum shows up. No formula needed.
- Opens big files fast — only renders visible rows, so 100MB CSVs don't lag.
- Column filters, group-by summaries, find-in-sheet.
Reads .xlsx / .xlsm / .xls / .csv / .tsv. Free, runs on macOS / Windows / Linux.
🔗 https://lazysheet.brata.cloud
Early release — happy to take feature requests or feedback. What would make this part of your workflow?
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Hunter
🚀 LazySheet v0.5.0 is out!
Thanks everyone for the support 🙏 Just shipped a big update:
🔍 Grid zoom 50–200% — ⌘ + scroll, keyboard, or the status bar
🧮 Cell formulas — now supported, and you can copy formulas between cells
🗄️ Export to SQL — turn any sheet into INSERT / UPDATE / UPSERT statements
♻️ Auto-updates (OTA) — install once, it keeps itself current
⚡ ⌘O to open files, ⌘W to close a sheet
Plus fixes: OS "Open with" now works on every platform, Fedora EGL crash gone, and group-by totals handle numeric text correctly.
Still free, open source, no account, no telemetry.
LazySheet v0.6.0 is out — and it's the biggest speed + size jump yet. A ~71k-cell .xlsx that used to take ~3 seconds now opens in well under a second (only the visible sheet is parsed up front), and the installed app shrank from ~25 MB to ~10 MB.
What's new in v0.6.0:
⚡ Much faster open — lazy sheet parsing; switching sheets no longer re-parses the whole workbook
📦 Half the size — ~25 MB to ~10 MB installed
🎨 Theme customization — built-in Material Theme palettes, picker moved into Settings
Still the same focused viewer underneath: opens .xlsx, .xlsm, .xls, .csv, .tsv, preserves formatting (merged cells, frozen panes, hyperlinks), pivot-style group-by summaries, range stats, formula support, export to SQL, grid zoom. Built with Tauri (Rust + web). Free, open source, cross-platform.
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🚀 LazySheet v0.5.0 is out!
Thanks everyone for the support 🙏 Just shipped a big update:
🔍 Grid zoom 50–200% — ⌘ + scroll, keyboard, or the status bar
🧮 Cell formulas — now supported, and you can copy formulas between cells
🗄️ Export to SQL — turn any sheet into INSERT / UPDATE / UPSERT statements
♻️ Auto-updates (OTA) — install once, it keeps itself current
⚡ ⌘O to open files, ⌘W to close a sheet
Plus fixes: OS "Open with" now works on every platform, Fedora EGL crash gone, and group-by totals handle numeric text correctly.
Still free, open source, no account, no telemetry.
⬇️ Grab it: https://lazysheet.brata.cloud
Would love to hear what you'd want next 👇
LazySheet v0.6.0 is out — and it's the biggest speed + size jump yet. A ~71k-cell .xlsx that used to take ~3 seconds now opens in well under a second (only the visible sheet is parsed up front), and the installed app shrank from ~25 MB to ~10 MB.
What's new in v0.6.0:
⚡ Much faster open — lazy sheet parsing; switching sheets no longer re-parses the whole workbook
📦 Half the size — ~25 MB to ~10 MB installed
🎨 Theme customization — built-in Material Theme palettes, picker moved into Settings
🛠️ Redesigned Settings — wider modal, Zed-style rows, toggle switches, inline language & theme pickers
🗂️ Workspace side panel — with an ask-before-close prompt so you don't lose unsaved work
✨ Window polish — scrolling long filenames, persistent resizable footer, centered titlebar, macOS resize-gap fix
Still the same focused viewer underneath: opens .xlsx, .xlsm, .xls, .csv, .tsv, preserves formatting (merged cells, frozen panes, hyperlinks), pivot-style group-by summaries, range stats, formula support, export to SQL, grid zoom. Built with Tauri (Rust + web). Free, open source, cross-platform.