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Oxipng

by Oxipng

Free plan APILinuxMacSelf-hostedWindows

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What Oxipng is

Oxipng is a free, open-source optimizer for PNG and APNG images. The multithreaded project began in 2015 as a rewrite of OptiPNG and is distributed under the MIT license. It runs as a command-line utility, offers an API, and can be used as a library in Rust programs. Batch processing is supported across Linux, macOS, Windows, self-hosted systems, and API workflows. Optimization settings range from -o 0 through -o 6 and include an -o max preset, with -o 2 as the default. Higher settings can take longer, and smaller output is not guaranteed for every file. The --strip option removes safe, all, or selected metadata chunks. For transparent images, --alpha may improve compression by changing fully transparent pixels, a technically lossy change. APNG optimization is limited to alpha optimization, refiltering, and frame recompression. Installation routes include Windows releases, package managers, Cargo, source builds, and Docker images for linux/amd64 and linux/arm64.

Who it suits

Oxipng suits developers and image workflows that need scriptable PNG or APNG optimization, Rust integration, or batch processing. It is also suitable for self-hosted and container-based deployments.

What it does well

  • Free, open-source software under the MIT license
  • Command-line utility and Rust library interfaces
  • Batch processing and API access are supported
  • Metadata can be stripped selectively
  • Docker images support two Linux architectures

What to know first

  • APNG transformations are limited
  • Alpha optimization is technically lossy
  • Higher settings can take longer
  • Smaller output is not guaranteed

Verdict

Oxipng provides configurable PNG and limited APNG optimization through command-line, API, and Rust interfaces. Its free licensing and broad installation options suit technical workflows, while APNG and alpha-processing limits require attention.

Facts from Oxipng's own pages

Animated PNG
Oxipng supports limited APNG optimization, including alpha optimization, refiltering, and recompression of frames; transformations are disabled. · github.com, 12 Oct 2026
API access
Yes · github.com, 20 Sept 2026
APNG limit
APNG optimization is limited to alpha optimization, refiltering, and recompression of frames; other transformations are disabled. · github.com, 11 Oct 2026
Batch processing
Yes · github.com, 20 Sept 2026
Compression
It offers optimization levels 0 through 6 and a max preset; higher levels can improve compression but take longer, with diminishing returns. · github.com, 12 Oct 2026
Compression modes
both · github.com, 20 Sept 2026
Containers
The project publishes a Docker image for linux/amd64 and linux/arm64. · github.com, 12 Oct 2026
Contributions and support
The project accepts contributions through GitHub pull requests and bug reports through GitHub issues. · github.com, 11 Oct 2026
Distribution
The README says Oxipng can be installed through Cargo or built from source with stable or nightly Rust. · github.com, 12 Oct 2026
Docker
A Docker image is available for linux/amd64 and linux/arm64. · github.com, 11 Oct 2026
Founded
2015 · github.com, 28 Sept 2026
Installation
The project documents Windows releases, package manager options, Cargo installation, and building from source; it recommends distro packages for macOS or Linux when sufficiently up to date. · github.com, 11 Oct 2026
Integrations
The README provides a pre-commit hook configuration for running Oxipng on a Git repository. · github.com, 12 Oct 2026
Interfaces
Oxipng is a command-line utility and can also be used as a library in other Rust programs. · github.com, 12 Oct 2026
License
The GitHub repository identifies the project as MIT licensed. · github.com, 12 Oct 2026
Metadata
Its strip option removes metadata using safe, all, or a specified list of metadata chunks. · github.com, 12 Oct 2026
Metadata controls
Yes · github.com, 20 Sept 2026
Metadata handling
The --strip option removes safe, all, or selected metadata chunks from processed images. · github.com, 11 Oct 2026
Optimization caveat
The README says higher optimization levels and Zopfli compression are not guaranteed to produce smaller output in every case. · github.com, 11 Oct 2026
Optimization levels
Optimization ranges from -o 0 through -o 6 or -o max; the default is -o 2. · github.com, 11 Oct 2026
Platforms
The README describes Windows downloads from GitHub Releases and recommends distro package repositories for macOS or Linux where available. · github.com, 12 Oct 2026
Project history
Oxipng began in 2015 as a rewrite of OptiPNG, with multithreading and Rust among its stated goals. · github.com, 11 Oct 2026
Purpose
Oxipng is a multithreaded PNG optimizer written in Rust. · github.com, 12 Oct 2026
Related software
The README lists ImageOptim, Squoosh, FileOptimizer, Curtail, pyoxipng, jSquash, and Trunk as software using Oxipng. · github.com, 11 Oct 2026

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