Open huge tables instantly.

less-sheet is a native, read-only tabular data viewer, focused on speed and low memory use whatever the file size. It supports CSV, CSV.gz and Parquet, from local files or HTTP(S) URLs.

It never loads the whole file into memory, only the minimum needed to fill the window.

Open from the file picker, the command line, a URL, or simply drop a file onto the window.

10 MB180 ms

10 GB180 ms

10 MB160 ms

10 GB160 ms

fresh process to data on screen

macoslinux

02

Benchmarks.

Time and memory to get your first look at the data. Both barely move as the file grows.^*

* Very wide CSVs — thousands of columns — do add to the load time.

Memory is the app at rest with the file open. Its footprint depends on the toolkit, graphics driver, and display. Times are medians of ten fresh process launches after a warm-up, with filesystem and driver caches warm. Memory is the highest of three samples per file size; figures are rounded to the nearest 5 ms and up to the next 5 MiB.

	CSV · 10 cols		CSV · 2000 cols		CSV.gz
size	open	memory	open	memory	open	memory
10 KB	180 ms	60 MiB	—	105 MiB	190 ms	65 MiB
10 MB	180 ms		225 ms		215 ms
10 GB	180 ms		225 ms		255 ms

MacBook Pro, Apple M2 Pro, macOS 26

	CSV · 10 cols		CSV · 2000 cols		CSV.gz
size	open	memory	open	memory	open	memory
10 KB	160 ms	100 MiB	—	135 MiB	150 ms	105 MiB
10 MB	160 ms		160 ms		190 ms
10 GB	160 ms		160 ms		195 ms

Linux · Intel Core i7-12700 · Samsung 980 PRO

03

Quick toggles for the most common parameters.

For CSV files, separator, quote character, header row and text encoding are detected from the file itself. You open the file and read it — there is no import step.

When a guess is wrong, each of those is a live control: change it and the open document re-renders in place. No closing, no re-importing, no starting over.

Separator and quote controls over the grid — separator guessed from the file — one click to override

separator guessed from the file — one click to override

04

Search, filter & sort.

Quickly find content across the entire file, or filter down to just the rows you need. Sort any column directly from its header.

Completed searches are remembered while you move between Find, Where and filtering, so returning to the same query does not scan the file again.

Copying returns the underlying values, regardless of any formatting you applied in the viewer.

Text search with live match count — live match count, every visible match highlighted

Typed column predicate — typed column predicates

live match count, every visible match highlighted

05

Where a spreadsheet struggles.

Spreadsheets like Excel and LibreOffice are powerful tools, built to edit and compute. But they load the whole file into memory, interpret its contents, cap how many rows it can have, and make changing the parsing options slow.

less-sheet loads the bare minimum and guesses the parsing options from the data. You can change them easily when it guesses wrong.

	Excel · LibreOffice	less-sheet
opening	Imports the whole file before showing anything	Reads only what is needed for the viewport
row limit	1,048,576	None
your values	Rewritten on import unless you catch it — leading zeros dropped, `1-5` becomes a date, long IDs go scientific	Never modified; copy returns the original
separator, quote	A one-shot import dialog, before you see the data	Live controls, after
memory	Scales with the file	Flat

06

Free. Tiny. No account. No telemetry.

macOS and Linux, both available now.

macOS

Download 0.1.9 · .dmg

macOS 26.0+ · Apple silicon · 3 MB

Homebrew

brew tap te-x/tap
brew trust --cask te-x/tap/less-sheet
brew install --cask less-sheet

Homebrew will not load a third-party tap until you say so. The middle line trusts this one cask, not the whole tap.

curl

curl -fsSL https://github.com/te-x/less-sheet/releases/download/v0.1.9/less-sheet-0.1.9-macos-arm64.tar.gz | tar -xz -C /Applications

First launch needs one extra step. less-sheet is not notarized by Apple, so the .dmg and the Homebrew install are both blocked once. Press Done — not Move to Trash — then open System Settings → Privacy & Security and press Open Anyway. The curl line is not affected.

Linux

Download 0.1.9 · Flatpak

x86_64 · runs on any distribution

Flatpak

flatpak remote-add --if-not-exists flathub https://dl.flathub.org/repo/flathub.flatpakrepo
flatpak install ./less-sheet-0.1.9-x86_64.flatpak
flatpak run com.lesssheet.LessSheet

Uses the GNOME 49 runtime, which Flatpak fetches from Flathub if you don’t already have it. The first line only adds Flathub as a source; on most desktops it is already there.

tarball

curl -fsSL https://github.com/te-x/less-sheet/releases/download/v0.1.9/less-sheet-0.1.9-linux-x86_64.tar.gz | tar -xz
./less-sheet/install.sh

x86_64 and aarch64 · 1.1 MB · installs to ~/.local/bin, no root
Uses your system’s GNOME libraries, so it follows your theme — but needs glibc 2.34+, GTK 4.20 and libadwaita 1.8.
Debian 13 ships GTK 4.18 and will not run this build. Use the Flatpak.