windows-rs lets you call Windows APIs - past, present, and future - directly from Rust. It is not a single crate but a family of them, from low-level API access to high-level declarative UI. This page helps you find the right crate for the job; each crate's own documentation then covers how to use it, with examples.

• Samples
• Releases

A family of crates

Most of these crates are small and focused - string types, error handling, the registry, collections, and so on - and you depend only on what you actually use. For broad, exploratory access to the entire Windows API surface, the windows and windows-sys crates project everything past, present, and future, gated behind per-namespace features.

For most projects, prefer the focused crates below, and generate a minimal, project-specific binding with windows-bindgen for any additional APIs you need.

Choosing your crates

Start with what you are trying to do and add the smallest crate that covers it. Follow the link for usage and examples.

If you need	Use
Windows error handling (HRESULT, Error, Result)	windows-result
Windows string types and macros (HSTRING, PCWSTR, h!, w!, s!)	windows-strings
COM/WinRT type support (IUnknown, the Interface trait, cast, GUID)	windows-core
To declare or implement a COM/WinRT interface	windows-core (#[interface] / #[implement])
Stock WinRT collections (IVector, IMap)	windows-collections
WinRT values (IReference<T>, TimeSpan, DateTime)	windows-reference, windows-time
Graphics math (vectors, matrices)	windows-numerics
WinRT async bridged to Rust futures	windows-future
The Win32 thread pool	windows-threading
The Windows registry	windows-registry
To author a Windows service	windows-services
The OS version at runtime	windows-version
To link C-style functions without import libs (link!, raw-dylib)	windows-link
To generate your own focused bindings	windows-bindgen
A declarative WinUI 3 UI, 2D graphics, a WebView, or a window	windows-reactor, windows-canvas, windows-webview, windows-window

Crates

The full categorized index follows. Each crate has one page under crates/ covering both usage and internals - how the crate is built and maintained (the tool_bindings / tool_reactor / tool_package codegen pipeline, generated files, and conventions). Each crate's own readme.md is the user-facing introduction with a quick example, and the per-crate page links to it. Item-level API reference is the generated rustdoc on docs.rs, linked from every page.

Core & error handling

Crate	Description
windows-core	Fundamental COM and Windows type support, including the #[interface] / #[implement] authoring macros.
windows-result	Windows error handling and propagation.
windows-strings	Windows string interop types and macros.

The #[interface] and #[implement] macros are part of windows-core, split into the windows-interface and windows-implement crates only because Rust requires procedural macros to live in a dedicated proc-macro crate.

Values & collections

Crate	Description
windows-numerics	Graphics math types (vectors and matrices).
windows-collections	Stock WinRT collection types.
windows-reference	Stock IReference<T> implementation.
windows-time	WinRT TimeSpan and DateTime.

Async & threading

Crate	Description
windows-future	WinRT async bridged to Rust futures.
windows-threading	Safe wrapper over the Win32 thread pool.

System services

Crate	Description
windows-registry	Safe Windows registry access.
windows-services	Author Windows services in Rust.
windows-version	Query the Windows version at runtime.

COM authoring macros & linking

These crates package functionality that is part of other crates but must ship separately. windows-interface and windows-implement are part of windows-core (see above); Rust requires their proc macros to live in a dedicated proc-macro crate.

Crate	Description
windows-implement	#[implement] proc macro for COM/WinRT - part of windows-core.
windows-interface	#[interface] proc macro for COM interfaces - part of windows-core.
windows-link	Raw-dylib import support (link!).

UI & graphics

Crate	Description
windows-reactor	Declarative UI library backed by WinUI 3.
windows-canvas	2D graphics built on Direct2D.
windows-composition	Retained-mode visual layer built on the Windows composition engine.
windows-webview	Safe wrapper around the WebView2 browser control.
windows-window	Minimal window creation and message loop.
windows-animation	Wrapper around the Windows Animation Manager.
windows-reactor-setup	Windows App Runtime installer for reactor apps.

Codegen & metadata tooling

Crate	Description
windows-bindgen	Code generator for Windows metadata.
windows-clang	Generates RDL from C/C++ headers using libclang.
windows-metadata	Low-level ECMA-335 metadata library.
windows-rdl	RDL parser and ECMA-335 generator.
riddle	Windows metadata compiler.
cppwinrt	Bundles the C++/WinRT compiler.

Full Windows API projection

These crates project the entire Windows API surface. For new projects, prefer a focused binding generated with windows-bindgen, or compose the smaller crates above.

Crate	Description
windows	Safer projection of C-style, COM, and WinRT APIs.
windows-sys	Zero-overhead raw bindings for C-style Windows APIs.

Building & maintenance

• Dependencies - every external SDK, header set, metadata file, and runtime the build and tooling depend on: what version is used, where it is set, how it is obtained, and how to update it.