prototyping

The 1st Collaborative AI Design Agent Workspace. Local-first and open source. Create motion, prototypes, websites, apps, dashboards, presentations, images, and videos with your team and AI agents. Share work, exchange feedback, and iterate together in one workspace.

Penpot: The open-source design platform for Product teams that need scalable collaboration.

Collection of custom elements that appear hand drawn. Great for wireframes or a fun look.

The Pencil Project's unique mission is to build a free and opensource tool for making diagrams and GUI prototyping that everyone can use.

Design and prototype customized UI, interaction, navigation, transition and animation for App Store ready Apps in Interface Builder with IBAnimatable.

Mockoon is the easiest and quickest way to run mock APIs locally. No remote deployment, no account required, open source.

Run Claude Design locally as an Agent Skill — Cursor, Codex, DeepSeek Harness & more. Produce polished UI mockups, prototypes, decks & wireframes as self-contained HTML, without claude.ai/design. Best with Opus or Claude.

Agent skills for useful HTML artifacts, wireframes, interactive prototypes, plans, and diagrams.

🎨 React application prototyping tool for developers and designers 🏗️

dnd visual editor - mockups and code in one go!

Turn Python scripts into handouts with Markdown and figures

DEPRECATED: Multiplatform GUI Prototyping/Wireframing

DeepSeek Harness 可编辑设计系统：AI 生成、可视化编辑、模板市场与 PPT｜Native Design & PPT Studio for DeepSeek Harness.

Quickly try out any Swift pod or framework in a playground

A Ruby DSL for prototyping card games.

Pro-grade UI design built into the coding agent you already use — GitHub Copilot Chat, Claude Code, Codex, Cursor. 270+ design skills, 150+ brand design systems, 160+ remixable examples. No desktop app, no daemon, no API keys — just files in your repo.

✔️ Mock data for your prototypes and demos. Remote deployments to Zeit now.

Browser-based MDX editor

Mmock is an HTTP mocking application for testing and fast prototyping

Charm: A Framework for Rapidly Prototyping Cryptosystems