Moonbrew

The concept promised a drink chosen by the stars, and never said how the stars would choose.

Problem
A specialty coffee shop wanted an app that reads your birth chart and the current moon to pick your drink. What existed was two concept documents: no flows, no screens, no rules.
Bet
Guest access before any chart is read: a View Menu door for the people who just want coffee.
My work
Product designer, solo, no design review. 19 screens across 6 flows, a design system, and the recommendation engine built from scratch. No user research was conducted and nothing here was validated: every number is output, not outcome.
Stance
A concept is not a feature until someone writes down the rules.
A long café hall lit from a glazed skylight: arched windows down the left side, brass dome pendants over a deep blue tiled counter on the right, a framed full moon and the word Moonbrew on the wall behind it, and a mezzanine with a bookshelf at the far end.

Nobody had defined the core feature. I wrote the rules, and they became the product.

Moonbrew is a specialty coffee shop where your drink is chosen by the stars. The owner’s brief described the experience in prose: no wireframes, no user flows, and nothing that said which chart produces which drink.

Three problems sat inside that idea, and none of them had an answer written down.

I also designed a way out for the people who would not play along.

Sign in, on navy: a rounded card framed in white and filled with a navy wave pattern, with a diamond badge holding a steaming cup at its centre, and under it an email field reading your@email.com, a password field reading Enter your password, a Continue button and a You dont have an accout? Sign up line. The home screen under a header of a full moon and the words Moon In Cancer: a card framed in white, navy inside, with the Aries glyph in a white notch at the top, an espresso martini over an engraving of a ram and a helmeted figure, the name Espresso Martini Mocktail, and the word Aries on the white base. A bottom bar reads Home, Menu, Orders and Rewards, with Home selected. The same Aries card on the home screen, this one all text: Hello Valeria!, then Not everything needs to happen today, then Today's energy, Earth refining: quiet precision, and Ready to sip what the universe picked? Your Aries urgency meets Virgo's patience. The details matter more than the speed. Then the word Aries on the white base. The bottom bar reads Home, Menu, Orders and Rewards, with Home selected. The menu, under a back arrow and the header Moon In Cancer: four white drink cards in two rows, each topped with a droplet icon, reading Ember Strike Double Espresso, Aurora Butterfly Pea Latte, Velvet Embrace Hot Chocolate and Emerald Dream Pistachio Latte. The bottom bar has Menu selected. The customization screen on cream, under a back arrow and the header Moon In Cancer: Elige el tamaño, marked Required, with radio buttons for Crescent (8oz), Half Moon (12oz) at plus $1.00 and Full Moon (16oz) at plus $1.00; Tipo de Leche, marked Required, with Whole Milk, Almond Milk at plus $0.75 and Oat Milk at plus $0.75; Sweetness with None, Light and Regular; and an Add to Order button at the bottom. The order screen: a Dark Whisper Espresso Shot described as Espresso, pistachio cream, steamed milk, in Half Moon (12oz) with Oat Milk and Light, quantity 1 at $9.72 with a minus and plus stepper. Below it a Pickup Location of 123 Cosmic Street, Suite 100, ready in about 10 minutes, with a Change button; a Rewards row headed Complete all 8 to unlock Free Brew! with eight moon phases, the first one filled, reading 1/8 phases complete; an Agregar Artículos button; and an Apple Pay button.

The spec said recommend a drink, and I had to decide what that meant

The concept described a personalized drink based on your birth chart without defining any underlying logic. Nobody asked for this deliverable. Each sign’s element sets a flavor temperament: fire bold, earth rich, air light, water deep. Each of the eight lunar phases sets an energy modifier: new moon calms, full moon amplifies. Four elements by eight phases is 32 drink and copy pairings, documented so a developer could implement them. Building the engine added roughly two weeks to my timeline. Without it the dev team had no spec to build from, and the core feature was still a concept.

AI was a workflow tool throughout the project. I used Claude to process client documentation into structured user flows, to research astrology systems and translate them into product rules for the recommendation engine, and to accelerate design system documentation: token naming, component specs, and usage guidelines. The visual design, component architecture, and all 19 screens were mine.

The eight moon states on one side, and on the other the card the customer receives: a drink, one line of copy, and the reading that produced it.

32

drink and copy pairings, one for every combination the engine can produce None of them was ever tested with a customer.

These 32 pairings are the part that did not exist: the rules a developer could implement, written down and handed over.

The owner assumed everyone wanted the ritual

The original onboarding had 10 screens, including two full screen animations, before anyone saw a drink. I cut it to 6: one data point per screen, with cosmic visuals that frame the input as unlocking your chart instead of filling a form. My estimate is that time to first recommendation drops from over two minutes to under 60 seconds. That compares two specs on paper, not two people using them.

A reading corner: two brown leather armchairs facing a low wooden table with a lit amber lamp and folded newspapers on it, an open book on the left armchair and a cream throw over the right one, a fiddle leaf fig in a pale ceramic pot at the left edge, and a black steel staircase climbing off the right edge, on a floor of blue star-patterned tiles.
Looking up into dark timber trusses and a glazed skylight, with a fern hanging in a brass pot under a beam and a lit brass dome pendant on a long cord below it, and arched windows down the plastered wall at the left. A round marble table by a curtained window with an open newspaper and a dark blue cup of coffee on its saucer, and a black coat over the back of a bentwood chair, on a floor of blue star-patterned tiles.

I built 32 combinations and could not check a single one

The concept documents reflected the owner’s vision, and my job was to turn that ambiguity into something a team could build. So the engine shipped complete and unverified. If I did it again I would propose a two week pilot with four combinations before building all 32. Completeness without validation is the part I would handle differently.

“Personalization” means nothing without documented logic. That is product design, not just UX.

The gaps in the original spec were the most valuable part of the project. Each gap was a decision I had to make, and those decisions are what made the product shippable.