Fluidd is a free, open-source Klipper web UI for 3D printers. See how it works with Moonraker, its features, install options, and how it compares to Mainsail.
Fluidd is a free, open-source web interface purpose-built for Klipper, the 3D printer firmware that moves motion planning off the printer's microcontroller and onto a companion computer such as a Raspberry Pi. Rather than being installed on the printer itself, Fluidd runs as a Vue.js and TypeScript single-page application that loads in any modern browser and communicates with Moonraker, the API server that bridges Klipper and web-based front ends, over the local network.
The project is maintained by the fluidd-core organization on GitHub, with the underlying repository created in September 2020 and now carrying a GPL-3.0 license, around 1,800 stars, and roughly 590 forks. It is entirely volunteer-driven, with no parent company, headquarters, or venture funding behind it, and it is sustained through community donations via GitHub Sponsors and support from hardware sponsors such as LDO Motors.
Fluidd's dashboard is responsive across desktop, tablet, and mobile screens and includes an interactive G-code viewer for previewing toolpaths, live thermal charts for extruders and the heated bed, and support for multiple simultaneous webcam feeds over MJPEG, HLS, or WebRTC. File management lets users upload, organize, and preview G-code, while a macro panel exposes custom Klipper commands for quick access during printing.
Because Fluidd is a pure front end for the Moonraker API, a single installation can manage and switch between several independent Klipper printers, which makes it a practical choice for small print farms as well as single-printer hobbyists. The project also integrates with popular Klipper-ecosystem add-ons including Kalico, Happy Hare, Beacon, and Obico, and ships built-in multi-language localization and print-history tracking.
Fluidd has no paid tier, license key, or subscription of any kind: the full application is free to download, self-host, and use under the GPL-3.0 open-source license. There is no feature gating between a 'free' and 'pro' version because there is only one version.
Ongoing development is funded through voluntary community support rather than product revenue, primarily via GitHub Sponsors, along with backing from hardware sponsors in the 3D printing space such as LDO Motors. Users who want to install Fluidd can choose among several free paths, including the KIAUH installer, official Docker images, a manually deployed release archive, a source build with Node.js and pnpm, or the hosted app.fluidd.xyz browser client.
Yes. Fluidd is entirely free and open source under the GPL-3.0 license, with no paid plans. Development is funded through voluntary donations via GitHub Sponsors and hardware sponsors such as LDO Motors.
Klipper is the firmware that controls the printer's motion; Moonraker is the API server that exposes Klipper's state and functions over the network; Fluidd is the web-based front end that connects to Moonraker to give users a visual dashboard and controls.
Fluidd is an alternative to OctoPrint rather than an add-on for it. Most users choose one interface for day-to-day printer control, though Moonraker can be configured to coexist with an OctoPrint installation on the same host in some setups.
The most common method is the community KIAUH installer, which sets up Klipper, Moonraker, and Fluidd together. Alternatives include official Docker images, a manually deployed release archive served over NGINX, building from source with Node.js and pnpm, or using the hosted browser client at app.fluidd.xyz.
Both are free, open-source, GPL-licensed web interfaces that use the same Moonraker API, so neither is objectively better. Mainsail generally offers more built-in customization and a community macro store, while Fluidd is often described as lighter and more responsive, particularly on lower-powered hardware.
Fluidd is maintained by the fluidd-core organization, a group of volunteer developers and community contributors. The project originated in the Voron 3D printer builder community, with the GitHub repository created in September 2020, and continues to receive regular updates from its maintainers and open-source contributors.