Qbs

Qbs is a free, cross-platform build automation tool for software projects in any language or toolkit. It suits developers who want to express build tasks and dependencies declaratively, particularly those working in Qt Creator or Visual Studio Code. Its broad documented target support is useful, but experimental project generators and limits on less-tested platforms make it a less certain fit for every environment.

Overview

Qbs models a build through its tasks and their dependencies rather than a prescribed sequence of build steps. That approach can accommodate projects built with different languages, toolkits, and libraries, and its extensible architecture offers room to adapt. The manual also describes incremental builds as correct and fast. By default, Qbs parallelizes work across all available CPU cores, though users can set a specific concurrent job count.

Qbs is open source and costs nothing. Its library and tools are available under commercial licenses, LGPL version 3, and GPL version 2. That choice gives teams licensing options, but they should select terms compatible with how they develop and distribute their software.

Key features

• Declarative build descriptions: Defining tasks and dependencies instead of build order can make the build model a natural fit for projects whose components and relationships matter more than a fixed sequence.
• IDE support: Qt Creator and Visual Studio Code support Qbs projects through the Qbs session feature. This is a practical advantage for developers already using either environment.
• Project generation: Qbs can generate projects for Visual Studio, IAR Embedded Workbench, and Keil uVision, but the manual calls this feature experimental. Treat it as a possibility to evaluate, not a dependable foundation for a workflow that requires generated projects.
• Build outputs: Qbs can generate Clang compilation databases, useful for workflows that consume that format. Its Makefile generator has a notable restriction: it refuses to create a Makefile if the source, build, or install root path contains spaces.

Pricing

Qbs costs nothing. There are no paid tiers to weigh against a reduced free version: the project is open source, and the library and tools are offered under commercial licenses, LGPL version 3, and GPL version 2. Teams choosing Qbs should focus on which license fits their use and distribution rather than comparing plan quotas or seat limits.

Platforms

Qbs documents built-in support for Windows, Linux, macOS, Android, iOS, tvOS, watchOS, QNX, and FreeBSD, as well as cross-compilation. Binaries are available for Windows, macOS, Linux, and FreeBSD, and Qbs can also be built locally from source. Other UNIX and Unix-like platforms may work, but are not regularly tested or officially supported; organizations targeting those systems should account for that uncertainty before standardizing on Qbs.

Who it's for

Qbs is a strong candidate for developers managing software across multiple platforms who prefer a declarative build model, especially when Qt Creator or Visual Studio Code is already part of their workflow. It is also worth considering for projects that need cross-compilation or a Clang compilation database. It is a weaker choice when a dependable project generator is essential, when the Makefile path restriction conflicts with the repository layout, or when official support is required for an undocumented UNIX-like system.

Pros and cons

• Pro: The build model applies across languages, toolkits, and libraries, so Qbs is not limited to one development stack.
• Pro: Documented targets span desktop, mobile, and embedded systems, with cross-compilation support.
• Pro: CPU-wide parallel builds are the default, with a configurable concurrent job count.
• Con: Project generation for Visual Studio, IAR Embedded Workbench, and Keil uVision is experimental, limiting its suitability for workflows that depend on it.
• Con: The Makefile generator cannot handle spaces in the source, build, or install root directory.
• Con: Other UNIX-like platforms lack regular testing and official support.

Alternatives

Consider fastlane for a free, open-source alternative available across Android, iOS, Linux, macOS, and Windows. Bazel is another free open-source build and test tool, with Linux, macOS, and Windows support. For a free tier with explicit usage allowances, Nx offers Hobby at no cost forever, with 50,000 credits that reset monthly, five contributors, and ten concurrent CI connections.

Other free options include FASTBuild, whose license permits commercial use and redistribution; SCons, licensed under MIT; Apache Ant, which requires Java 8 or later and is distributed in ZIP, TAR.GZ, and TAR.BZ2 formats; and Apache Maven, which uses Apache License 2.0 and requires JDK 8 or later for Maven 3.10. Buck2 is a free open-source build system from Meta.

Verdict

Choose Qbs if you want a free build system with declarative project descriptions, broad documented target support, and an existing Qt Creator or Visual Studio Code workflow. Its flexible build model is the main reason to choose it; look elsewhere if you need a proven project generator, or official support for platforms outside its documented set.