Famous Applications Written in C and C++: From Operating Systems to Games

Here is a fun exercise: try to get through one hour of your day without touching software written in C or C++. Your phone’s operating system? C at the core. The browser you are reading this in? C++. The database behind your banking app, the engine rendering tonight’s game session, the interpreter running the world’s Python code — C and C++, all the way down.

This article is a guided tour of the most famous software built with the two languages — operating systems, browsers, games, databases, creative tools, embedded and financial systems — and, just as importantly, an honest look at why these domains still choose C and C++ decades after both languages were declared obsolete for the first time.

Table of Contents

• The Short Answer at a Glance
• Operating Systems: Windows, Linux and macOS
• Web Browsers: Chrome, Firefox and Safari
• Games and Game Engines Written in C and C++
• Databases: MySQL, PostgreSQL, SQLite, Redis and MongoDB
• Language Runtimes: The Software That Runs Other Software
• Creative and Productivity Software
• Embedded, Automotive and Aerospace
• Financial Systems: Where Microseconds Are Money
• Why Is So Much Software Still Written in C and C++?
• Key Takeaways
• Frequently Asked Questions
• Conclusion

The Short Answer at a Glance

If you are learning either language right now, this list is your motivation: our C tutorials and C++ tutorials teach the same tools these systems are built with.

Operating Systems: Windows, Linux and macOS

The clearest demonstration of C’s staying power is that every mainstream operating system kernel is written in it.

Microsoft Windows. The Windows NT kernel — the core of Windows 10 and 11 — is written mostly in C, with substantial C++ throughout the wider OS, drivers, and user-mode components. Microsoft has begun introducing Rust into selected kernel and system components as part of its memory-safety push, but the foundation remains C/C++ and will for decades: there are hundreds of millions of lines of it.

Linux. The Linux kernel — running everything from all of the world’s top supercomputers to most web servers and every Android phone — is written in C (with assembly where needed). Rust graduated from experiment to permanent, first-class kernel language at the 2025 Kernel Maintainers Summit, and new drivers in some subsystems can now be written in it, but the kernel’s tens of millions of existing lines are C and are not being rewritten.

macOS and iOS. Apple’s XNU kernel is C (with C++ used in the I/O Kit driver framework). The layers above mix C, Objective-C, and Swift — but the part that talks to hardware is the same story as everywhere else.

Android. The kernel is Linux (C); the native layer, graphics stack, and media frameworks are heavily C/C++, with apps sitting on top in Kotlin/Java.

Web Browsers: Chrome, Firefox and Safari

The program you are using right now is one of the largest C++ codebases on Earth.

• Google Chrome is built on the Chromium project — tens of millions of lines of C++ — including the Blink rendering engine and the V8 JavaScript engine, which also powers Node.js. Google has additionally opened the door to Rust for new third-party-facing components, but Chromium is and remains a C++ project.
• Mozilla Firefox is C++ at the core, famously mixed with Rust components (Mozilla created Rust; the Stylo CSS engine came from that work) and JavaScript for UI.
• Apple Safari runs on WebKit, written in C++.
• Microsoft Edge has been Chromium-based since 2020 — the same C++ under a different shell.

The reason browsers stay in C++ is the same reason games do: a rendering engine racing to paint your screen in under 16 milliseconds cannot afford unpredictable pauses, and C++ gives engineers exact control over memory layout and timing.

Games and Game Engines Written in C and C++

This is the category readers ask about most, so let’s be specific.

The engines are C++. Unreal Engine — currently at version 5.8, with Unreal Engine 6 announced for early access around late 2027 — is written in C++, and gameplay programming in Unreal is done in C++ (plus Blueprints). Unity’s core runtime is C++ even though gameplay scripting is C#. Valve’s Source 2, id Software’s id Tech, and CD Projekt Red’s REDengine — all C++. We maintain a full catalog in our list of 100+ game engines written in C/C++.

Famous games written in C++ (usually via those engines): Fortnite, Counter-Strike 2, League of Legends, Valorant, DOOM Eternal, Cyberpunk 2077, Elden Ring, and effectively every AAA console title of the past two decades. Minecraft is the great teaching example: the original Java Edition is Java, but the Bedrock Edition that runs on consoles, phones, and Windows was rewritten in C++ — largely for performance and portability.

Games written in C are mostly the foundational classics: the original DOOM (1993) and Quake (1996) were C, and their open-sourced code remains some of the most-studied game code ever published. Modern solo developers still choose C with libraries like raylib or SDL, but the industry mainstream is firmly C++. If you are weighing options for your own project, our guide to the best programming languages for game development compares C++, C#, GDScript and more with current market data.

Databases: MySQL, PostgreSQL, SQLite, Redis and MongoDB

Nearly every byte of the world’s stored data passes through C or C++ on its way to disk:

• MySQL — written in C++ (with C), the database behind a huge share of the web; source on GitHub.
• PostgreSQL — written in C, the most-loved relational database in developer surveys year after year.
• SQLite — pure C, and by deployment count arguably the most widely used software library in existence: it ships inside every Android and iOS device, every major browser, and countless applications.
• Redis — written in C; the standard in-memory data store.
• MongoDB — the flagship document database, written in C++.

Databases showcase the languages’ other superpower besides speed: predictability. A storage engine must know exactly when and where every byte moves — garbage-collected languages make that guarantee much harder.

Language Runtimes: The Software That Runs Other Software

Here is the fact that most delights new C programmers: the “easier” languages are themselves C/C++ programs.

• Python — the standard implementation is literally named CPython: an interpreter written in C.
• Java — the HotSpot JVM at the heart of the Java platform is written in C++.
• JavaScript — Google’s V8 engine (Chrome, Node.js, Deno) is C++.
• PHP, Ruby, Perl — C interpreters, all.
• The compilers, too: GCC and LLVM/Clang — the toolchains that build nearly all native software, including each other — are C++ projects.

When someone says Python is “slow but productive,” the productive part is Python; the parts that are fast — NumPy’s math kernels, for instance — drop down into C.

Creative and Productivity Software

• Adobe Photoshop, Illustrator, Premiere Pro — C++ codebases decades in the making; Adobe remains one of the most active corporate contributors to the C++ community.
• Microsoft Office — Word, Excel, and PowerPoint are largely C++ (with roots in C), which is part of why a 40-year-old spreadsheet product still opens instantly on a laptop.
• Autodesk Maya and AutoCAD — the film industry’s 3D pipeline and engineering’s drafting standard, both C++ with C++ plugin SDKs.
• Blender, VLC, OBS Studio, FFmpeg — the open-source media stack is C and C++ end to end; FFmpeg (C) alone decodes video inside YouTube, VLC, and practically everything else that plays a file.

Embedded, Automotive and Aerospace

Away from screens, C rules absolutely:

• Cars — a modern vehicle runs tens of millions of lines of code across dozens of electronic control units (ECUs), overwhelmingly C (with C++ growing in infotainment and driver-assistance stacks under standards like AUTOSAR and MISRA).
• Space — NASA’s JPL famously flies its rovers on C under some of the strictest coding standards ever written, and SpaceX has publicly described its Falcon and Dragon flight software as C/C++ running on Linux.
• Everything with a chip in it — medical devices, routers, TVs, industrial controllers, and the firmware inside your keyboard. When the target has kilobytes of RAM and hard real-time deadlines, C is often the only serious candidate.

Financial Systems: Where Microseconds Are Money

High-frequency trading is the purest expression of why C++ exists: firms compete on latencies measured in microseconds and nanoseconds, and C++ dominates the field because it lets engineers control memory layout, avoid allocation on the hot path, and squeeze deterministic performance from hardware. Bloomberg, whose terminal sits on hundreds of thousands of finance desks, runs on C/C++ infrastructure and maintains major open-source C++ libraries (BDE) and its own C-based database, Comdb2. Exchanges’ matching engines — the software that pairs your buy order with someone’s sell — are C++ for the same reason.

Why Is So Much Software Still Written in C and C++?

Four reasons come up in every one of the systems above:

1. Performance with predictability. No garbage-collection pauses, no runtime surprises. For a game frame, an audio buffer, or a trade order, consistent speed matters as much as raw speed.
2. Total control of memory and hardware. C/C++ let you decide exactly how data is laid out and when it moves — essential for kernels, drivers, engines, and databases.
3. Run-anywhere portability. A C compiler exists for effectively every processor ever manufactured, from an 8-bit microcontroller to a supercomputer.
4. Forty years of ecosystem. Billions of lines of proven code, libraries, and institutional knowledge. Rewriting Windows or Unreal Engine is not an engineering decision; it is a decade and a fortune.

The honest caveat: the industry is changing at the edges. Security agencies and big tech firms have spent the last few years pushing memory-safe languages, and Rust is now a permanent resident of the Linux kernel, a component language in Windows and Chromium, and the default choice for some new systems projects. What that pressure has produced is coexistence, not replacement — new components in Rust alongside C/C++ cores — while the C++ committee responds with its own safety work. For a deeper treatment of this exact question, see our analysis of whether C/C++ is still relevant in today’s tech landscape.

Key Takeaways

• Every mainstream operating system kernel — Windows NT, Linux, macOS XNU — is written in C, with C++ throughout the layers above.
• Every major browser (Chrome, Firefox, Safari, Edge) is a C++ codebase at its core.
• The games industry runs on C++: Unreal Engine (now at 5.8), Unity’s runtime, Source 2, and virtually all AAA titles; the foundational classics DOOM and Quake were C.
• The world’s databases (MySQL, PostgreSQL, SQLite, Redis, MongoDB) and language runtimes (CPython, the JVM, V8) are C/C++ programs — even “easy” languages stand on C.
• Embedded, automotive, aerospace, and high-frequency trading remain C/C++ strongholds because of deterministic performance and hardware control.
• Rust is now genuinely present at the systems level — permanent in the Linux kernel, growing in Windows and Chromium — as a coexisting language, while the installed C/C++ base keeps growing.

Frequently Asked Questions

Conclusion

The pattern across every category in this list is the same: wherever software meets hardware, deadlines, or scale, C and C++ are there — usually invisibly, always foundationally. That is a more interesting claim than “C++ is fast.” These languages persist because entire industries have bet their most valuable systems on them, and those bets keep paying off.

For a learner, the practical takeaway is that this stack is unusually open. The kernel in your phone, the database in your projects, and the engine behind last night’s game are all source code you can read today — and our guide to whether C++ is still a good language to learn will help you decide where to start.