4B Pen vs Paper

4B Pen

4B Pen is a desktop design IDE that keeps your design, its code and your agent in one project folder, and ships it to a live URL.

Paper is a design tool whose canvas is built on HTML and CSS, with an MCP server so AI agents can read and edit designs.

Feature	4B Pen	Paper
Design canvas	Pages, layers, auto layout, components and variables. Opens .fig files.	A canvas built on web standards, with frames, flex layouts, components, tokens and shaders.
Code	Code files open in tabs beside the canvas. Build turns a design into an app in your project folder.	Designs are HTML and CSS underneath; agents can read JSX or Tailwind for a layer.
AI agent	Bring your own: Claude Code, Codex, Gemini CLI and others run in the built-in terminal with your subscription.	Connect your agent through Paper’s MCP server.
Deploy	One click to Cloudflare from the app.	Not a hosting tool; you deploy the code elsewhere.
Where files live	On your computer, as a project folder. Works offline.	Stored by Paper. See paper.design for details.
Price	Free on your computer. Cloud and Team are coming later.	A free tier and a paid plan. See paper.design.

About Paper as of October 2026, from paper.design and public reviews. Something changed? Tell us and we’ll fix it.

Pick Paper when you want a web-native canvas and your code lives in another editor you already like.

Pick 4B Pen when you want to design, build with your own agent and ship a live app without leaving one window, and keep the files on your computer.