Download
Get the installer for your OS from the Releases page.
Introduction
Columnar is a native desktop application for opening and exploring CSV and TSV files of any size.
Most spreadsheet tools struggle or crash with files over a few hundred megabytes. Columnar handles hundreds of millions of rows by indexing the file on open and reading rows on demand — memory usage stays low regardless of file size.
It is intentionally minimal. No cloud sync, no formulas, no editing. Just a fast, clean viewer you can drop any dataset into.
Installation
See the installation guide for platform-specific steps.
Keyboard shortcuts
Learn the shortcuts to navigate faster.
How it works
Understand the lazy loading architecture behind Columnar.
Why Columnar?
Section titled “Why Columnar?”Most tools fall into two camps — full spreadsheet editors (Excel, LibreOffice) that load everything into RAM, or command-line tools that require scripting knowledge. Columnar sits in between: a GUI tool with the performance characteristics of a command-line tool.
| Tool | 14 GB file | Memory usage | GUI |
|---|---|---|---|
| Excel | Crashes | All of it | ✓ |
| LibreOffice Calc | Very slow | All of it | ✓ |
xsv / csvkit | Fast | Low | ✗ |
| Columnar | Fast | Low | ✓ |
Tech stack
Section titled “Tech stack”Columnar is built with Tauri v2 — a framework for building lightweight native desktop apps with a Rust backend and a web frontend. The CSV parsing and virtual scroll are implemented in Rust using memory-mapped files and parallel processing via Rayon.
The frontend is vanilla HTML, CSS, and JavaScript with no framework or bundler.