A wealth of open-source projects exists, just below the visible surface of the apps you use from day to day. They may not be high profile or widely appreciated, but they enable everything from networking and statistical analysis to the next generation of AI agents.

Discover more about these vital codebases that are more accessible than you’d expect.

NumPy

Hardcore math processing

Python excels in the fields of data analysis, visualization, and machine learning. The highly popular library, NumPy, is at the heart of all three, and any code that relates to scientific computing.

As its name suggests, the library is aimed at numerical tasks in Python. Fundamentally, this includes support for large, multidimensional arrays (matrices) and associated functions.

NumPy acts as the core for several other libraries, including Pandas, AstroPy, and Shapely. It has also been used as the basis for GPU-accelerated computing on the NVIDIA CUDA platform.

OpenCV

For collaborative visionaries

This library contains over 2,500 algorithms, available under the Apache license, to help facilitate real-time computer vision. It’s also a solid example of a codebase that uses our previous entry, NumPy.

Credit: OpenCV

OpenCV is used by Google, Microsoft, and Sony. Even NASA, the American space agency, uses this open-source code, which is quite an endorsement. However, it’s the use of OpenCV on every smartphone that really means it warrants a place on this list.

Computer vision often goes hand-in-hand with machine learning applications, so the boom in Artificial Intelligence has seen renewed interest, to the extent that OpenCV.ai has been launched to capitalise and deliver large-scale solutions. You can expect to hear more about this codebase in the coming years.

WinUI

A Microsoft take on open source

Microsoft hasn’t always had the most cordial relationship with open source; its founder, Bill Gates, famously considered the paradigm a threat to Microsoft’s business. It could be argued that the company’s entire business model, based on a strategy of “embrace, extend, extinguish,” was antithetical to the open-source movement.

But that all changed in the 2000s, when Microsoft began to release some of its work under open-source licenses and started to contribute to open-source projects run by others. This effort increased substantially with Sadya Nadella’s appointment as CEO, and one of the most visible results—although you’d be forgiven for letting it pass you by—is WinUI.

WinUI is central to Universal Windows Platform apps that run across different versions of Windows, on devices from PCs to tablets and Xbox. Like most open-source projects, WinUI’s code is shared on GitHub, the platform that Microsoft acquired under Nadella.

gRPC

Enabling diverse systems to communicate efficiently

gRPC (gRPC Remote Procedure Calls) is an open-source framework that enables fast communication of binary data over a network. Originally developed by Google in 2016, it’s available for all under an Apache License.

Credit: gRPC

gRPC is a high-performance alternative to REST, the current industry standard for web services. While gRPC is more complex, it is also more efficient and has provisions for schemas to enforce valid data.

Many companies have adopted gRPC, so you’re almost certainly using it all the time without knowing it. Uber, Netflix, Spotify, and Dropbox all make use of the technology.

XNU

Not quite Linux, not BSD, but a vital part of macOS

If you’re an Apple user, you’ve also used XNU, whether you run iOS, macOS, or even watchOS. It’s the kernel, famously based on software acquired from NeXT, that, in conjunction with code from the FreeBSD project, went on to power OSX and revitalize Apple’s fortunes.

XNU’s architecture offers a compromise between a monolithic kernel and a microkernel, making it flexible and fast.

If you’re committed, you can download and compile the kernel from GitHub. It’s available as a project under Apple’s OSS Distribution account, which also hosts open-source parts of macOS, iOS, and WebKit.

FreeType

Transforming text everywhere

Credit: FreeType

Much of what we do on computers involves text, and that text would be nothing without fonts; at least, it would be pretty uninspiring. Freetype gives developers a helping hand with any font-related tasks they may encounter.

For some time, this library was forced to play second fiddle to Apple’s admittedly superior font technology, mainly because Apple Inc. owned patents it infringed upon. But, since 2019, the code can once again make use of its font hinting and color filtering tech, and it’s now very widely used—ironically, even by Apple. They’re in good company, though: FreeType is also used by Linux, Android, Roku, and Chromium, among others.

FreeType essentially acts as a layer between font files (in various formats, like TTF, OTF, and WOFF) and applications that need to use them. It implements features like rasterization, anti-aliasing, and kerning. The code is also popular with video game developers, and platforms like Sony’s PlayStation line ship with Freetype.

SDL2

The library behind many of your favorite games

A cross-platform library, with a focus on multimedia applications and video games, SDL (Simple DirectMedia Layer) is written in C and provides bindings for other languages.

While SDL isn’t a game engine itself, it’s used by engines like Valve’s Source to produce games such as Half-Life, Portal, and The Stanley Parable. It’s also used in multimedia applications and to write emulators.

The latest versions of SDL are licensed under the less common zlib license, which allows for static linking in proprietary code. This has, in theory, simplified the distribution of closed-source games, which are an important part of SDL’s target market.

Norigin Spatial Navigation

Take remote control

If you’ve ever wondered about the tech that powers your Smart TV’s interface, wonder no more; at least, when it comes to one specific aspect. Navigating a UI with a mouse, keyboard, or touchscreen can be tricky, but with a basic remote control—which may differ wildly from model to model—it’s complicated further. Thankfully, the awkwardly-named Norigin Spatial Navigation package is here to help.

Credit: Norigin Media

Norigin Spatial Navigation has ambitions beyond TVs and set-top boxes. The library can work on any web-based platform, in addition to React Native apps on Android TV and Apple TV.