The best UI Design alternative to Mockup Builder is Pencil Project, which is both free and Open Source. If that doesn't suit you, our users have ranked more than 25 alternatives to Mockup Builder and 12 are UI Design Tools so hopefully you can find a suitable replacement. Other interesting UI Design Tool alternatives to Mockup Builder are Lucidchart, Napkins.dev, Frame0 and Balsamiq Wireframes.
Pencil is a standalone app that lets you create diagrams or UI mockups. It doesn't have collaboration/multi-user features.
Lucidchart is a cloud-based platform that promotes teamwork through diagramming, collaboration, and data visualization. It serves millions worldwide, offering flowcharts, UML, real-time collaboration, Visio support, and browser access. Designed for innovation and understanding, it integrates easily into workflows.
An open source wireframe to app tool powered by Llama 3.2 vision. Upload a screenshot of a simple site/design & get code.
Sketch your app ideas without stress Make hand-drawn style wireframes quickly and easily.
Low-fidelity UI wireframing tool simulating sketching experience, optimized for speed with Quick Add, built for collaboration, drag-n-drop simplicity, exportable wireframes to PNG/PDF, interactive prototypes via linking, hundreds of UI components, reusable symbols, and more.
Feature-rich, open-source Wireflow offers a collaborative platform for online creation of complex user flow prototypes. Ideal for team work in UI design, wireframing, and mind mapping, promoting idea sharing in real-time environment aided by modern whiteboard features.
A streamlined web app that helps you create and collaborate in real-time on wireframes, mockups, diagrams and prototypes.
Quant-UX is an integrated Prototyping and Analytics software. It allows you to design, test and analyze interaction prototypes.
Online tool for creating mockups in the browser. Use your browser’s save function to save the file (just html for view only, complete save for an editable version) or export to codepen for others to view.
Mockplus is a desktop-based prototyping tool. It can be used to create wireframes/mockups/prototypes for any mobile and web apps with ease. This tool will make UI/UX designers prototype faster, smarter and easier.
MockFlow accelerates early-stage product design and ideation with AI-powered wireframing, prototyping, and visual brainstorming. WireframePro and IdeaBoard enable teams to collaboratively transform initial concepts into professional, shareable wireframes and diagrams.
Automatically connects to your Photoshop document and converts your mockups into interactive prototypes using layer comps to organize your documents into screens. Transition between them by defining hotspots in the layer name you want to be tappable.
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extreme intuitive and easy... no bug related