Moqups

Penpot

Penpot is a web‑based, open‑source design and prototyping tool that lets UI/UX designers create wireframes, mockups, and interactive prototypes. It offers a collaborative environment similar to commercial alternatives while keeping data under your control. Because it is open source, teams can self‑host Penpot on their own infrastructure or use the free cloud offering, making it a flexible choice for freelancers, startups, and enterprises that need cost‑effective design workflows.

MockFlow

MockFlow is a wireframing and online whiteboard platform that helps teams visually brainstorm, wireframe, and design user interfaces, combining IdeaBoard for AI-enhanced whiteboarding with WireframePro for structured UI wireframing using 100+ pre-built components. It supports screenshot-to-wireframe and text-to-wireframe AI generation and can export designs to code including React, Tailwind, and Flutter.

Uizard

Uizard is an AI-powered UI design platform aimed at people who need presentable mockups fast but don't have deep design skills. Its Autodesigner 2.0 engine can generate a full multi-screen app or web project, including a matching theme and components, from a single text prompt, while a Wireframe Scanner turns a photographed hand-drawn sketch into an editable digital screen and a Screenshot Scanner rebuilds existing apps or websites into editable mockups. Beyond generation, Uizard supports real-time multiplayer editing so product, design, and marketing teams can work on the same project, an AI Design Assistant that lets users restyle elements with plain-language instructions, and developer handoff export to React and CSS. It is positioned less as a replacement for full-featured design tools and more as a fast path from idea to clickable prototype for product managers, founders, and agencies.

Justinmind

Justinmind is a design and prototyping platform used to build web and mobile app interfaces ranging from low-fidelity wireframes to high-fidelity interactive prototypes. It offers vector-based UI design tools, reusable design systems and UI kits, and interaction features like web animations, transitions, and mobile gestures such as tap, swipe, pinch, and scroll. The platform is used by teams at companies including Adobe, Google, and Cisco, and combines prototyping with requirements management, letting teams embed and track requirements directly inside prototypes. Finished work can be tested on iPhone, iPad, and Android through companion viewer and emulator apps, and exported as HTML, SVG, PNG, or developer specification documents.

Marvel

Marvel is a design platform that lets teams wireframe, design, and prototype digital products, then test them with real users and hand them off to developers. It is used by organizations ranging from startups to Fortune 100 companies, and includes Ballpark, a companion tool for running user research and surveys against Figma prototypes.

Whimsical

Whimsical is a visual workspace that enables users to create flowcharts, wireframes, and mind maps. It provides a collaborative platform for teams to brainstorm, plan, and design projects. With Whimsical, users can create diagrams, wireframes, and mind maps using a variety of templates and tools. The platform also allows real-time collaboration, making it easy to work with team members and stakeholders.