Side by side

MozJPEG vs Scalir

Both stand on image compression software. Which one you can start free with, which one lets you read the code, and what each costs once you pay.

MozJPEG

Free plan APILinuxMac+2

MozJPEG is a library for programs seeking improved JPEG compression while retaining broad decoder compatibility. The included cjpeg tool is only a demo, so the project is aimed at library integration rather than serious command-line use.

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Scalir

Free plan LinuxSelf-hostedWeb+1

Choose Scalir for local bulk image compression, resizing, and conversion, with a choice of hosted, desktop, or self-hosted use. Look elsewhere if you need a separate macOS desktop build or an unlimited hosted session.

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The facts

	MozJPEG	Scalir
Free plan	Yes	Yes
Open source	Not published	Not published
Runs on	API, Linux, Mac, Self-hosted, Windows	Linux, Self-hosted, Web, Windows
Lowest paid plan	Free or on request	Free or on request
Plans published	1	1
Maker	Not published	Not published
Website	github.com	scalir.org
On image compression software	#14 of 85	#10 of 85

MozJPEG: what it does well

Compatible with the JPEG standard.
Integrates through the libjpeg API.
Progressive encoding can losslessly reduce JPEG size.
Improvements can be disabled at runtime.
Build instructions cover macOS, Linux, and Windows.

What to know first

The cjpeg command-line tool is described as a demo.
The project points elsewhere for additional build help.
The repository page states no security certifications or compliance claims.

Scalir: what it does well

Processes image files locally on the device.
Supports eight image input formats.
Can run batch jobs across CPU cores.
Provides precise resizing options without upscaling.
Open source under the MIT license.

What to know first

The hosted app has a small soft per-session limit.
There is no separate macOS desktop build yet.
The PWA works offline only after its first load.

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