The best open source alternative to Figma is excalidraw. If that doesn't suit you, we've compiled a ranked list of open source Figma alternatives to help you find a replacement.
Figma is a browser-based design tool used for creating user interface mockups, interactive prototypes, and design systems, with real-time multiplayer editing that lets teams work on the same file simultaneously. It also includes FigJam, a whiteboard tool for brainstorming and diagramming alongside the core design product.
People look for open-source alternatives to Figma for different reasons depending on what they use it for. Some want to avoid per-seat pricing for larger design teams, others want design files stored locally or on their own infrastructure instead of Figma's cloud, and some are specifically looking for a lighter whiteboarding or diagramming tool rather than a full UI design suite.
Excalidraw fits the whiteboarding and diagramming side of this comparison rather than the full UI design workflow. It is an open-source, sketch-style drawing tool for flowcharts, wireframes, and diagrams, with a hand-drawn visual style and real-time collaboration similar to FigJam. It is not a replacement for Figma's vector design and component system, so teams doing detailed interface design work will not find a full equivalent here, but for whiteboarding, planning, and quick diagrams it covers similar ground.
When choosing between these tools, be clear about which part of Figma you are trying to replace. If your main need is collaborative diagramming or sketching, Excalidraw is a reasonable open-source substitute, and it can be self-hosted or embedded into other tools. If you need full UI design with components, auto layout, and design handoff to developers, look for a more complete design-focused alternative, since no single open-source tool yet covers Figma's full design feature set.