Past code-backed. The prototype is the code.
UXPin saw the problem clearly: prototypes drift from production because they are built from drawings. Its answer is design with real React components, now with an AI assistant. Prototyper takes the last step: the prototype is the code, written by your agent on a shared canvas.
Last reviewed
What UXPin does well
Interaction depth
States, variables, expressions and conditional logic without writing code. Far past what static design tools simulate.
Code-backed components
Merge brings React components in from Git, Storybook or npm, so prototypes use production pieces. Forge, its AI assistant, generates layouts from those same components.
Design system discipline
Colors, typography, components and guidelines documented in one place, the kind of tooling design system teams put to real use.
Where Prototyper is different
The artifact is a codebase
A UXPin prototype arranges real components inside a design editor. A Prototyper screen is a React and TypeScript app on the canvas, ready to commit.
Agents do the assembly
You describe or sketch; Claude Code, Codex or Cursor builds on the canvas over MCP. Nobody wires interactions together by hand.
No editor between idea and code
There is no design-tool layer to keep in sync with the codebase. The agent writes code against the workspace files directly.
Bring your own agent
Your own coding agent runs on the subscription you already pay for, and a built-in agent covers quick edits.
Side by side
| Prototyper | UXPin | |
|---|---|---|
| Prototype is a React app you can commit | Yes | partial |
| Interactions with states and logic | Yes | Yes |
| AI generation from a prompt or image | Yes | Yes |
| Use your own AI | Your coding agent over MCP | Your own API key in Forge |
| Design system documentation tooling | No | Yes |
Checked against UXPin's official pages on 6 October 2026; tell us if something is out of date.
Which one to pick
Pick UXPin when
- You have a production React library to sync into design
- Designers build detailed interaction logic by hand
- You need design system documentation with guidelines
- You want AI layout generation from your own components
Pick Prototyper when
- You want an AI-native UXPin alternative that starts free
- The prototype should be React code you commit
- You want Claude Code, Codex or Cursor to build the screens
- The team reviews live on one multiplayer canvas
Backed by code, or made of code
UXPin deserves credit for naming the real problem years before AI made it fashionable: prototypes lie when they are built from drawings. Merge attacks that by bringing production React components into the design tool, and Forge now generates layouts from those same components and shows the JSX behind them.
A Merge prototype is still an arrangement inside a design editor, though, and engineering builds the application around it. Prototyper closes that gap. The canvas holds actual React and TypeScript files, the screens on it are those files running, and shipping means committing the code, not translating a simulation of it.
Who does the assembly
UXPin is a power tool, and interaction logic with variables, expressions and conditions is a skill worth respect. Forge speeds up layout, but the interactions are still built in the editor, and the prototype has to be maintained as the idea changes.
On Prototyper the assembly is delegated. You put the intent on the canvas, a sketch, a sticky, a sentence, and your agent constructs the working screen, states and logic included. Revision is a note, not an evening.
Two takes on AI-native
Forge is a capable assistant: it works from your connected component library, accepts prompts and images, lets you choose between Claude and GPT models, and can run on your own OpenAI or Anthropic API key. If your design system is already in UXPin, that is a strong reason to stay.
Prototyper is built around the agent rather than adding one. Claude Code, Codex, Cursor or another MCP client joins the canvas as a worker with a real file system: it reads and writes files, runs commands and places objects. The agent your engineers use can be the agent your designers use.
What engineering inherits
The end of a UXPin project is a specification with excellent evidence: a high-fidelity prototype, documentation, and honest components. Engineering still starts a build, translating composition and logic into an application.
The end of a Prototyper project is code. Connect GitHub to the workspace, and the screens the team tested go to the repository as a pull request that an engineer, or the same agent, continues from. The handover meeting becomes a code review.
Moving over, or running both
Teams deep in a Merge deployment do not need to unwind it to try this. Pick one upcoming feature with real interaction, brief it on a Prototyper canvas, and let the agent build it. Then compare the path from idea to user test against your current cycle, and compare what engineering inherits at the end.
There is no prototype import; the idea travels, not the file. Drop screenshots of the current prototype onto the canvas and the agent rebuilds it as a running app. Design system documentation can stay in UXPin, and nothing about the trial commits you to moving it.
Frequently asked questions
- How is this different from UXPin Merge?
- Merge brings your production React components into a design editor, so the prototype uses honest pieces. On Prototyper there is no editor to sync: the prototype is React code your agent writes, and shipping means committing it.
- How does Prototyper compare with UXPin Forge?
- Forge generates UI inside UXPin from your connected component library, and can use your own OpenAI or Anthropic API key. Prototyper lets an outside coding agent, such as Claude Code, build the screens as code directly on the canvas.
- Can it handle complex interaction logic?
- Yes. Because screens are real code, any state, condition or flow an application can have is available. You describe the behavior; the agent implements it.
- Do I need engineering support to start?
- No. Sign in, open a canvas, and start with a sketch or a sentence. Connecting GitHub comes later, when there is something worth committing.
- Is Prototyper a UXPin replacement?
- For prototyping product screens as code, yes. For governed design system documentation, UXPin has purpose-built tooling, and some teams will run both.
Sources
- UXPin: Merge, accessed
- UXPin: Forge, accessed
- UXPin Docs: What is Forge, accessed
- UXPin Docs: Interactions, accessed
- UXPin Docs: Expressions, accessed
- UXPin Docs: Design Systems, accessed
See it against your current tool.
The fastest way to compare is to put an agent on the canvas and watch it build. Free to start, no credit card.