QOI file format: what it is and how to use it

QOI is the Quite OK Image format: a one-page spec delivering lossless compression close to PNG at a fraction of the complexity and speed cost. Learn when to use it and what to choose instead.

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What is a QOI file?

A .qoi file is an image in the Quite OK Image format, Dominic Szablewski's 2021 design proving a point: a spec that fits on one page, encodes and decodes at blazing speed, and still lands within ~10–20% of PNG's compression. It stores lossless RGB/RGBA in a stream of simple opcodes, the anti-thesis of image-format complexity.

When should you use QOI?

  • Speed-critical lossless paths: game assets, frame buffers, real-time pipelines.
  • Simple implementations: when you want a decoder you can audit in an afternoon.
  • Lossless intermediates: fast scratch storage between processing steps.

When is another format a better fit?

For anything stored or shared, PNG is the answer: better compression and universal support. For tiny fast lossless QOI is a niche choice even among specialists; for photos, lossy formats win anyway. QOI is brilliant engineering with a small addressable audience.

The short version: QOI is PNG-speed-simplified, a specialist's format for pipelines where milliseconds matter.

How to open a QOI file

On Windows

Double-click the file, or open it with GIMP (plugin).

On macOS

XnView opens QOI files on macOS.

In your browser

Open QOI files right in a browser tab or with the dexrr viewer. No install, no upload.

Also opens in

  • GIMP (plugin)
  • XnView
  • qoi tools
  • FFmpeg

View or convert QOI files

A quick preview or a new format. No install, no upload.

View QOI files Preview and inspect QOI files Convert to QOI Turn files into QOI QOI to PNG Portable Network Graphics QOI to BMP Windows Bitmap QOI to FF Farbfeld image

QOI technical details

Full name
Quite OK Image
Extensions
.qoi
MIME type
image/qoi, image/x-qoi
Magic bytes
71 6F 69 66 (qoif)
Compression
Lossless
Developer
Dominic Szablewski
Specification
qoiformat.org

QOI questions, answered

How do I open a .qoi file?

A growing list: GIMP, ImageMagick, qoiconv tools and game-engine plugins read it; OS viewers mostly do not yet. dexrr displays and converts qoi files in your browser.

Can I convert QOI files online?

Yes, dexrr converts qoi locally in your browser: QOI to PNG for universal use.

Is QOI better than PNG?

On speed and simplicity, dramatically; on compression and compatibility, no. It is a specialized tool, not a PNG replacement.

Why is my .qoi file bigger than the PNG?

That is the trade: QOI's simple opcodes compress less than PNG's filters, typically ~10–20% larger, in exchange for much faster processing.

Is the QOI format outdated?

Too new to be, but its niche (fast lossless pipelines) keeps it a specialist's choice rather than a mainstream format.