Penpot

Penpot is the first open-source design and prototyping tool that rivals mainstream competitors like Figma. Built on web standards (SVG), it offers a familiar, powerful interface for wireframing, visual design, and prototyping with a key differentiator: no vendor lock-in and the freedom to self-host. Its collaboration features are robust, supporting real-time co-editing. Being open-source means it's completely free for individuals and teams using the cloud version, and organizations can deploy it on their own infrastructure for full data control.

It supports design systems with components and is actively developed with a growing community. While its ecosystem of plugins and resources is smaller than Figma's, its core wireframing and design capabilities are strong and rapidly improving. It is ideal for privacy-conscious organizations, developers who want to contribute to their design tool, and teams seeking a powerful, free alternative to commercial platforms without usage restrictions.