PrusaSlicer 3.0 Preview Brings a Complete Rewrite and a Plugin Marketplace

The biggest PrusaSlicer update ever

Prusa Research released a public preview of PrusaSlicer 3.0 on September 1, 2026, exactly 15 years after the first commit to Slic3r, the open-source project PrusaSlicer was originally forked from. Josef Průša is calling it the largest set of changes in the software's history, and the details back that up.

The team rewrote the user interface from scratch. Tools now sit along the top of the screen, the left side gets a collapsible scene browser, and a contextual right-hand panel changes depending on whether you have a bed, an object, or a tool selected. A View Cube handles camera control. Users can pick between light and dark themes. Keyboard navigation schemes now match Tinkercad, Blender, SolidWorks, and Fusion 360, so switching between apps costs less mental overhead.

Multi-bed and multi-tool handling finally makes sense

The multi-bed feature introduced in PrusaSlicer 2.9.0 has been rebuilt. Each bed is now a fully independent part of a single project, with its own configuration. You can combine different printers and profiles inside one file, move models between beds, and slice beds in parallel. The old nine-bed limit is gone. The application also supports multiple open projects in separate tabs, and it now saves local backups automatically.

The profile system has been reworked to support multi-tool setups properly. Printers like the Prusa XL can now assign a different nozzle size to each tool head, and different print or printer profiles can apply per tool. Existing 3MF projects created in PrusaSlicer 2.x still load, with settings matched automatically to the new system.

A sandboxed plugin system and planned marketplace

PrusaSlicer 3.0 introduces a Lua-based plugin system that runs sandboxed. Plugins do not have access to the disk, external project data, or the network by default. Two plugins ship in the preview: a flow-rate calibration tower and a temperature calibration tower.

A community plugin marketplace is on the way. Prusa says it will include a rating system, and submitted plugins will go through a review process. Users can still install unverified plugins if they choose. The plugin API is marked as experimental and subject to change.

The release also adds a proper offline mode. When enabled, networking libraries are not loaded at all. Users can also disable individual online services, including Prusa Connect, Printables integration, and profile update checks, separately from the main offline toggle.

Why a full rewrite now

Průša attributed the scope of the rewrite to years of accumulated technical debt. He described situations where the team identified a bug but concluded that fixing it would cause something worse. The new architecture uses YAML for profile files, replacing the old .ini format. The preview installs alongside PrusaSlicer 2.x without conflicts, using a separate profile directory, so users can test without disrupting their existing setup.

Some functionality from 2.9.6 is not yet reimplemented. Prusa says those features will land in version 3.1.0. Third-party 3MF files from Bambu Studio or OrcaSlicer import as geometry only, without settings. STL, OBJ, and STEP files import as before.

PrusaSlicer 3.x is released under AGPLv3, the same license used for version 2.x, Slic3rPE, and the original Slic3r. The plugin marketplace and sandboxed architecture suggest Prusa Research is trying to keep its contributor ecosystem inside the PrusaSlicer project rather than losing developers to spin-off slicers.

Bug reports are being accepted through GitHub and the Prusa community forum. If you depend on a specific feature for daily work, the parallel-install design means you can test the preview without giving up your stable 2.x workflow.