Relm4

At a glance

• Editor score
  4.3 / 10
• Pricing
  Free plan
• Best for
  Rust developers building GTK4 desktop applications
• Free plan
  Yes
• Paid from
  Free
• UI stack
  Native
• Facts checked
  23 Oct 2026

• Where it wins

  • Declarative UI definitions pair with an Elm-inspired application model.
  • Supports GTK4 through gtk4-rs and works with libadwaita.
  • Reusable components and asynchronous tasks support structured desktop apps.

• Where it doesn't

  • Its UI stack is centered on GTK4 rather than multiple desktop frameworks.
  • It is designed for Rust developers, not teams working in other languages.
  • Its documented targets are desktop platforms, not mobile.

Our verdict on Relm4

Relm4 is an open-source Rust GUI library for building desktop applications on Linux, Windows, and macOS. Its intended audience is developers who want a native desktop interface in Rust and are comfortable with GTK4. The Elm-inspired application model gives apps a defined structure, while declarative, macro-based UI definitions let developers express interfaces in Rust. It is a focused framework rather than a general-purpose toolkit spanning several UI stacks, so its fit depends on choosing GTK4 for the project.

The main draw is how Relm4 combines its UI model with GTK4 and libadwaita. Built on gtk4-rs, it supports reusable application components alongside asynchronous background tasks and UI updates. That combination is relevant for apps whose interface needs to respond to work happening outside the main UI flow. Documentation includes getting-started material and examples, providing a route into the library's patterns. Developers should still expect to work within the GTK4 ecosystem; Relm4's value here is its Rust-oriented structure for that stack, not breadth across unrelated desktop frameworks.

Relm4 is free and open source, with a self-hosted deployment model rather than a paid application plan. The desktop reach covers Linux, Windows, and macOS, but mobile is outside its stated targets. The project also describes GResource bundles and an ecosystem starter template for Flatpak, so packaging considerations are tied to its GTK environment. Choose Relm4 if Rust, GTK4, and a component-based, Elm-inspired model match your application. If the project needs mobile targets or a different UI stack, a framework built around those requirements will be a better fit.

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Relm4 pricing

Relm4 fact sheet

Relm4 integrations

Relm4 lists 3 integrations on its own site.

• GTK4
• gtk4-rs
• libadwaita

Alternatives to Relm4

• FlutterAn open-source Dart framework for building cross-platform apps from shared UI code.9.3
• EElectronAn open-source framework for building desktop apps from a shared JavaScript codebase.9.1
• .NET MAUI.NET MAUI shares C# and XAML development across native mobile and desktop apps.9.0

See all Relm4 alternatives →

Featured on iTechGuides

Relm4 is listed in our Desktop App Development Frameworks directory. Add the badge to your site — it links back to this page.

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Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026

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Last updated 30 Oct 2026 · How we research and update