Where C++ is used
C++ is rarely visible on the surface, but many of the programs you use every day run on it. It's chosen where other languages can't deliver the required speed or control:
- image, video and audio processing, computer vision;
- games and game engines, 3D graphics, simulators;
- software for industrial equipment, medical devices and POS terminals;
- trading and financial systems where every millisecond counts;
- the core of databases, browsers and libraries that other languages then build on.
C++ isn't used for ordinary websites, online stores or customer portals. But a web system can absolutely rely on a C++ module that does the heavy lifting.
C++ strengths
- Maximum performance. A C++ program uses nearly the full power of the hardware, with no intermediate runtime.
- Control over resources. The developer decides how much memory to use and when to free it. This matters for resource-constrained devices.
- Works with everything. A C++ library can be called from Python, Java, C# and other languages, so an accelerated module can become part of any system.
- Mature libraries. Qt for interfaces, Boost for common tasks, and specialized libraries for graphics, networking and math.
Drawbacks to consider
- Complexity. C++ is one of the most complex languages. Development takes longer, and specialists are scarcer and more expensive than for web languages.
- Memory bugs. The freedom to manage memory brings the risk of leaks, crashes and vulnerabilities. Without strict discipline and verification tools, such bugs can hide in the code for years.
- Complicated builds. Libraries, compilers, settings for different operating systems — in older projects, the build often works only on one "right" machine.
- Slow feature development. Something that takes an hour to write in Python can take much longer in C++.
When you don't need C++
We recommend C++ only when there's truly no way around it. For a backend service that has to handle heavy load, Go is usually enough — it's also fast, but much simpler to develop in and safer in how it handles memory. For new system components where security matters, Rust is also worth considering.
If the problem is slow data analysis, it's often enough to use Python libraries properly — under the hood, they're already written in C++ and other fast languages. Writing a custom module only makes sense after measuring.
C++ as an accelerator for other languages
The most practical business scenario isn't writing the whole system in C++, but offloading one narrow but heavy operation to it. For example, the main service is written in Python, but recognition or image processing takes too long. We rewrite that piece in C++ and plug it into Python as a regular library.
The rest of the code stays simple and clear, while the heavy part can become several times faster. The key is to measure first whether the bottleneck really is where it seems to be.
Existing C++ software: support and modernization
Many companies run C++ programs written years ago — for warehouses, manufacturing, labs or equipment control. They do their job, but the author is no longer around, and the program can't exchange data with newer systems.
We take it step by step. First, we get the project building reliably with modern tooling and cover its current behavior with tests. Then we update the code to a modern language standard and eliminate memory leaks and unsafe spots. Our general approach to such systems is described on the legacy system modernization page.
Qt desktop applications
Qt is the library behind many desktop applications for Windows, macOS and Linux, from engineering software to operator workstations. These applications tend to live a long time and accumulate features.
When a Qt application needs further development, we first check which version of the library it runs on and whether its dependencies are outdated. Then we decide together with you: upgrade it to a newer Qt version, add features to the current one, or gradually move part of the workflow to a web interface so it can be used from any device.
Integration with web systems
Often a C++ program doesn't need rewriting — it needs to "talk" to the rest of the business. We add an API, data exchange via a database or files, or a connection to a message queue. After that, data from equipment or a desktop application flows automatically to your website, CRM or accounting system. Learn more about this kind of work on our integrations and automation page.
What affects the cost
- Code condition: whether the project builds, and whether there are tests, documentation and someone who remembers the logic.
- Platforms: one operating system or several; a server, a desktop or specialized hardware.
- Performance requirements: how much faster it needs to be and how we'll measure the result.
- Dependencies: third-party and proprietary libraries, hardware drivers, licenses.
- Integrations: which systems the program needs to exchange data with.
For existing projects, we start with an audit: it shows how much work stabilization requires and what can be postponed.
Frequently asked questions
Can our old C++ program be rewritten in another language? Sometimes, especially if speed isn't critical. But it's often cheaper to stabilize the existing code and add an API to it.
Do you work with embedded systems and microcontrollers? That's a narrow specialty. On the first call, we'll tell you honestly whether we can take on the task or whether you'd be better off with a specialized team.
How do we know we need C++ rather than another language? Start by measuring. If optimizing the existing code still doesn't deliver enough speed, then it makes sense to talk about C++.
Can you build a web interface for our C++ program? Yes. The program keeps doing the heavy work, while users control it and see results in a browser, with no installation on every computer.
Why Promodex
Our strength is seeing the system as a whole: the C++ module, website, mobile app and accounting software all have to work together. At Promodex, one team keeps an eye on all of it, with no work split among subcontractors, backed by the agency's experience of 750+ projects since 2015. We don't overcomplicate what can be kept simple, we explain every step transparently, and we stay on for support after the work is done.
