FASTBuild

FASTBuild is a free, open-source build system for developers who need to scale compilation across CPU cores and networked machines. Its strongest case is a compatible C++ toolchain and a team willing to configure workers; builds that rely on settings FASTBuild cannot distribute or cache get less benefit.

Overview

FASTBuild combines parallel compilation, reusable build results and network distribution in a small executable that requires no installation or external dependencies beyond compiler tools. The maker says independent developers and large studios use it across PC, Mac, Linux, console, smartphone and retro-system projects. The current release is v1.20, released 26-Apr-2026.

The maker claims build-time improvements of 10x or more over other build systems, and says caching can accelerate compile times up to 10x. Those are potential gains, not guarantees: some compiler settings prevent caching or distribution. FASTBuild builds affected objects locally when it detects those incompatibilities, which preserves the build path but reduces the payoff from shared resources.

Key features

Parallel builds, caching and distribution

Compilation tasks can run across worker threads, making use of available CPU cores without requiring a network of machines. A local or network cache can reuse compilation results between builds, especially useful when developers repeat work across a project. Distributed compilation can add capacity from other machines, but it depends on compatible settings, synchronized compilers, worker discovery and worker startup. Teams that cannot maintain those conditions should not count on remote execution as a reliable speedup.

Toolchains and targets

FASTBuild lists support for MSVC, GCC, SNC, Clang, GreenHills, CodeWarrior and NVCC, as well as command-line compilers with compatible syntax. Its listed targets include Windows, OS X, Linux, iOS, Android and major game consoles. This breadth is useful for studios spanning platforms, but target support alone does not remove the need for compatible compiler settings.

Unity builds and IDE workflows

Unity or Blob builds combine multiple C++ files, while writable files can still be built individually for quicker iteration. FASTBuild can generate Visual Studio and XCode project files, and its output is Visual Studio compatible. Third-party downloads include Unreal Engine integrations, build visualizers and editor support for Emacs, Sublime, Vim and VSCode; those extensions can help fit existing workflows, but they are third-party tooling rather than core capabilities.

Pricing

FASTBuild v1.20 — free. It is open-source software, with commercial use and redistribution permitted subject to license terms. There is no paid tier or trial to weigh against the free version; the license allows use for any purpose and alteration and redistribution under its conditions. It also provides the software as-is, without express or implied warranty, so organizations needing a warranty-backed product should look elsewhere.

Platforms

FASTBuild supports Linux, macOS and Windows. Its build targets extend to Windows, OS X, Linux, iOS, Android and major game consoles, making it relevant to cross-platform development even when the build system itself runs on desktop operating systems.

Who it's for

FASTBuild is a strong fit for individual developers and studios with established compiler workflows who want to reuse results or spread compilation across local cores and networked workers. Its range of listed compilers and targets favors teams managing substantial C++ builds across platforms. It is a weaker choice for projects whose compiler settings routinely block caching or remote execution, or teams that cannot configure and synchronize workers.

Pros and cons

• Pros: Free, open-source use includes commercial applications and redistribution under the license terms, avoiding a per-seat software charge.
• Pros: Parallel work, local or network caching, and remote distribution offer several ways to reduce repeated or slow compilation.
• Pros: A self-contained executable avoids installation and external dependencies beyond compiler tools, while listed toolchains and targets span many development environments.
• Cons: Incompatible compiler settings force affected objects to build locally or without caching, limiting acceleration on some projects.
• Cons: Distributed builds require compatible configurations, synchronized compilers, worker discovery and startup; teams must handle that setup to benefit.
• Cons: The as-is license disclaims warranty, a material drawback for buyers who require warranty assurances.

Alternatives

Choose fastlane instead if its Android and iOS platform coverage and MIT-licensed open-source plan better fit the project. Qbs is another free option for Android, iOS, Linux, macOS and Windows, with commercial, LGPL v3 and GPL v2 licensing choices.

Bazel is a free, open-source build and test tool from Google for Linux, macOS and Windows. Ninja is a free, speed-focused build system available as a binary or from source, also for those desktop operating systems.

Nx may suit teams seeking a freemium CI offering: its free Hobby plan includes 50,000 monthly-reset credits, five contributors, 10 concurrent CI connections and community support. qmake fits Qt Community Edition users who can meet its LGPL or GPL open-source obligations, including making source available to copy, modify and distribute; some Qt capabilities are limited.

SCons is a free MIT-licensed alternative for users who want permission to use, modify or redistribute it without charge. Shake is another free, BSD-licensed option, installed with Haskell Stack.

For broader comparisons, browse Build Automation Software or Game Build Automation Software.

Verdict

Choose FASTBuild if you compile substantial C++ projects with compatible settings and can configure dependable workers: its free license, cache and parallel or distributed builds provide a compelling route to more compilation capacity. Look elsewhere if your compiler configuration limits those features, worker setup is impractical, or you need warranty coverage.