Overview

Refract supports packs from Modrinth, CurseForge, and FTB, and keeps each setup in its own instance. Mods, resource packs, worlds, settings, and launch options stay separate, which helps players switch between configurations without carrying one pack’s changes into another. Existing libraries can be imported without mixing files or disrupting saves, and worlds are preserved during updates.

Refract is free software under the GNU GPL v3.0, and its application and website are developed in public. It uses Tauri and Rust for its native shell. Discord supports player help and project discussion; GitHub is used for bug reports, change proposals, and code contributions, with a separate discussion space for longer questions and ideas.

Key features

Pack discovery and import: Browse compatible content in the launcher, work with packs from Modrinth, CurseForge, and FTB, and import modpacks or existing libraries. This suits players consolidating pack management, though the supported sources are the ones named above.
Isolated instances: Keep mods, resource packs, worlds, settings, and launch options distinct for each setup. That separation is useful for players maintaining several packs or configurations.
Update management: Install mod dependencies and update individual mods in place; worlds remain preserved during updates. These tools reduce the need to rebuild a setup after routine changes.
Runtime and customization controls: Manage Java versions and memory limits, and adjust themes, accent colors, sidebar layouts, and launch behavior. The range is useful for tailoring a launcher to different setups without changing the instance-isolation model.

Pricing

Refract is free software, and a free plan is available. No paid tier or usage cap is identified, so it is a straightforward option for players who want a no-cost launcher. The Free software plan has custom pricing.

Platforms

Refract supports Windows, macOS, and Linux, covering the major desktop platforms for players choosing a launcher across those systems.

Who it's for

Refract is best suited to players who manage multiple modpacks, want to import an existing library safely, or prefer discovering and updating compatible content inside the launcher. Its open-source license and public development also make it a natural fit for users who value those project qualities. Players who do not need pack separation or in-launcher mod management may find its strengths less relevant.

Pros and cons

Pros: Separate instance files and preserved worlds help protect established setups during pack changes and updates.
Pros: Support for Modrinth, CurseForge, and FTB, plus import and in-launcher discovery, brings several pack workflows together.
Pros: Java management, dependency installation, and individual mod updates provide practical control over maintaining instances.
Cons: Its value is concentrated in modpack management; players looking for a different launcher focus may be better served elsewhere.

Alternatives

Minecraft Launchers is the broader directory for comparing launchers.
Prism Launcher is another free, open-source choice for Windows, macOS, and Linux.
LabyMod offers a free Java Edition plan for Windows, macOS, and Linux with support for 20+ versions, and also has a freemium model.
Thendrask Launcher is a free, MIT-licensed option with no paid tier or required subscription; it also offers a $3.00 USD per month End Crystal plan for project support.
Cactus MC Launcher offers a free-forever, open-source option with no premium tier or ads for Windows, macOS, and Linux.
ATLauncher is free and open source, but requires a paid Minecraft account to use the launcher and play modpacks.
Minecraft Launcher is free to download, while access to games requires ownership or a time-limited demo.
GDLauncher is free to use, with no premium tier or overlay.
FTB App is a free freemium option whose app contains ads; its source code is available through the project’s GitHub repository.

Verdict

Choose Refract if you want a free, open-source desktop launcher that keeps modpacks isolated while bringing discovery, imports, and update tools together. Its central advantage is safer, more organized management of separate setups; look elsewhere if those pack-management strengths are not what you need from a launcher.

	Refract	UltimMC
Free plan	Yes	Yes
Paid from	Free	Free
Platforms	Windows, macOS, Linux	Linux, macOS, Windows
Free plan	Yes
Separate instances	Yes	Yes
Modpack import	both
Mod loader support	multiple
Java runtime management	Yes
Built-in modpack catalog	Yes
Automatic updates	Yes	No

Refract vs UltimMC

Refract

UltimMC