C++ / Backend Engineer

We are looking for an experienced C++ / backend engineer to join on a short-term, time-bound basis to lead refactoring and modernization work on a mature desktop application. The product has a large, cross-platform C++ codebase (~500k lines of code plus third-party dependencies) built on Qt5. The primary goal of the engagement is to modernize the build toolchain and dependency stack, with the migration to Apple Silicon as the top priority.

Not all of the tasks below are guaranteed to be completed within the engagement. At a minimum, the Intel → Apple Silicon migration must be delivered; remaining items will be prioritized based on time and progress.
Responsibilities:
Migrate the macOS build of the application from an Intel to an Apple Silicon build (C++ codebase, ~500k LOC plus third-party libraries, Qt5).
Migrate third-party libraries from Conan 1.x to Conan 2 across the Windows, macOS, and Linux builds.
Update the Linux build to use Clang 19 (from Clang 11) and move the build to Ubuntu 24.04.
Update selected third-party libraries to recent versions to meet security requirements.
Migrate the codebase from C++17 to C++20.

Mandatory Skills Description:
Proficiency in modern C++ (17/20) and cross-platform development across Windows, macOS, and Linux.
Strong experience with CMake and build-system toolchain configuration.
Hands-on knowledge of the Conan package manager.
Familiarity with the Clang / LLVM toolchain.
Experience with Qt5 application development and macOS packaging / code signing.
Comfortable working with Docker-based CI/CD pipelines and large legacy codebases.