DesignEx Download for macOS

A Mac app that turns the coding agent you already pay for into a design partner.

DesignEx designs in your design system, shows you real prototypes, and hands the winning direction back to your repo as work your agent can implement.

Download for macOS Research preview

TLDR;

Create, iterate on, and compare prototypes: mobile apps, web and desktop apps, single pages, components, flows, landing pages, ads, slide decks. Every one of them in the design system it derived for your project.

The DesignEx project page for a bike-share project called Spoke: a design-system band naming Groupset and showing its token strip, a grid of twelve prototype previews, and a list of seven threads.
The DesignEx inspiration library: a search field over a dense board of saved reference screenshots, filtered by Interface, Materials, and Typography.
DesignEx reviewing a mobile prototype: the thread on the left explains the rider app's full ride path, and the workbench on the right renders it on a phone, over a conformance strip reporting 36 off-system values to reconcile.
DesignEx reviewing a web prototype: the thread on the left records a request to make the portal fully responsive, and the workbench renders the member portal's ride ledger with a route map and an itemised fare receipt.
DesignEx comparing two variants of the same station card side by side, each under its own revision header: on the left the pinned synthesis, which leads with the dock meter and keeps a reserve-a-bike line, and on the right option B, which leads with a map of the corner. A note beneath each states the argument it makes.

What it does

  1. 1Starts from what you have. Point it at a codebase, a Figma file, an image, a DESIGN.md, or pick a system from the built-in catalog.
  2. 2Designs in your system. Prototypes are real HTML wired to your tokens, not pictures of it.
  3. 3Lets you change your mind. Comment on the exact element, fork a direction, compare options side by side, keep what wins.
  4. 4Hands off cleanly. One push writes a build pack into your repo. Your coding agent implements it from there.
  5. 5Comes with taste. Design-engineering skills for direction, typography, color, motion, and accessibility ride along with every project, and the references you save become a library both you and the agent can search.

What it needs

A Mac, and a subscription you already have: Claude Code, Codex, Cursor, or OpenCode. DesignEx works with your existing account.

An iOS companion app lets you review prototypes and leave comments away from your desk.

What it is not

It is not another coding agent. Yours is already excellent at building. It is just not a place to look at design, weigh two directions against each other, or change your mind cheaply. That part is DesignEx.

It is not a mockup tool. The prototype is real markup in your real tokens, so nothing has to be redrawn or translated later.

Status

DesignEx is a research preview. It is early, it is Mac-only, and rough edges remain. If that is acceptable, it is ready to use today.

The prototype is the spec.

Download for macOS Research preview