less-sheet
Minimal, fast CSV viewer that streams large files without loading them into memory, opening multi-gigabyte files in under 200ms
🔗 Visit less-sheet
Description
Opening a huge CSV file in a spreadsheet program is often where things go wrong — the app tries to load every row into memory at once, and a multi-gigabyte export either takes minutes or crashes the program entirely. less-sheet is built around the opposite idea: only load the handful of rows currently visible on screen, no matter how big the file actually is.
less-sheet is a read-only CSV viewer that streams data — plain or gzipped, local or remote — without ever loading the full file into memory, achieving roughly O(viewport) performance regardless of file size. Both a 10MB file and a 10GB file open in the same 75-182 millisecond range, and it's been tested against files with over 135 million rows. It's free, open source, and available for macOS and Linux.
💬 Our review
The short version: if you regularly get handed enormous CSV exports that choke Excel or Numbers, less-sheet is worth keeping around specifically for the moments a spreadsheet app gives up — it's free, fast, and does one job without trying to be a spreadsheet editor.
Against Tad or VisiData, which are also built for large tabular files, less-sheet's pitch is narrower and more extreme on speed: it's read-only by design, trading editing capability for genuinely constant memory usage at any file size. That tradeoff makes sense if your actual need is "look at this data quickly" rather than "edit this data," and csvkit remains the better choice if you need to transform or query the file rather than just view it. The lack of a Windows build is the main practical gap — Linux and macOS users get the speed benefit, Windows users are stuck with heavier alternatives for now.
📊 Global score
🤖 AI-enriched data
Gratuit, open source.
Pros
Ouvre des fichiers CSV de plusieurs gigaoctets en 75 à 182 millisecondes
Consommation mémoire quasi constante quelle que soit la taille du fichier
Testé avec succès sur des fichiers de plus de 135 millions de lignes
Cons
Lecture seule, aucune édition ou modification des données possible
Limité aux fichiers CSV, pas d'autres formats tabulaires
Disponible uniquement sur macOS et Linux, pas de version Windows