Bazel vs Qbs

Bazel is a free, open-source tool for automating software builds and tests across languages and platforms. Projects define targets in BUILD files using Starlark, which can also be used to create custom rules and macros. Bazel caches prior work and rebuilds what needs to change, while running tasks in parallel. It supports languages including C++, Java, Kotlin, Python, Go, and Rust, with outputs for desktop, server, Android, and iOS. Bazel runs on Linux, macOS, and Windows, and the documentation describes builds with 100,000 or more source files across multiple repositories. Sandboxing can make builds and tests more hermetic, and failures return a non-zero exit code for basic CI integration. Teams can share outputs through a remote cache, but must select and maintain its backend and secure access because it can contain binaries. IDE options include plugins for IntelliJ, Android Studio, CLion, and Visual Studio Code, plus Xcode integration. Bazel is not well suited to uncached deployment steps that change cloud configuration.

Qbs is a build automation tool for managing software projects across multiple platforms. Projects can use it regardless of programming language, toolkit, or libraries, and its declarative model lets them describe build tasks and dependencies without setting the build order. The manual lists correct, fast incremental builds and an extensible architecture among its features. Qbs documents built-in support for Windows, Linux, macOS, Android, iOS, tvOS, watchOS, QNX, and FreeBSD, plus cross-compilation. It can be used with Qt Creator and Visual Studio Code through the Qbs session feature, and it can generate Clang compilation databases. Project generation for Visual Studio, IAR Embedded Workbench, and Keil uVision is available but described as experimental. Binaries are available for Windows, macOS, Linux, and FreeBSD, or Qbs can be built locally from source. The Qbs plan costs nothing. Its library and tools are available under commercial licenses, LGPL version 3, and GPL version 2. The Makefile generator will not create a Makefile if the source, build, or install root directory contains spaces; other UNIX-like systems may work but are not regularly tested or officially supported.