# Guilherme Ribeiro

> CMO & Head of Product · Product Designer · Praia Grande · SP · Brazil · https://guilhermeribeiro.art/

Guilherme Ribeiro is a product designer and Head of Product based in Praia Grande · SP · Brazil. He took Reune, a restaurant operations SaaS, from an idea to a funded company, on more than thirty restaurants of field research, and owns its brand, its product design and its front-end. He designs at library scale, including a thirty-four component design system with a written governance model, and writes the code that ships it. Trained in consumer neuroscience at Copenhagen Business School, cognitive psychology at Cambridge and neuroscience at Harvard.

Designer at the intersection of product, neuroscience and code — engineering interfaces where usability, scalability and human behaviour converge.

## Selected work

### Reune Digital
Reune Digital · 2024 — present · Head of Product · Design · Brand
Case study: https://guilhermeribeiro.art/portfolio/reune/

A management system for Brazilian restaurants, taken from an idea to a funded company. Orders, tables, till, stock, kitchen and delivery in one place, with five sales channels landing in a single queue.

Research first: more than thirty restaurants visited before anything was drawn. I am Head of Product, and the brand, the product design and the landing page are mine.

Tags: SaaS, Product Strategy, Research, Brand, Front-end

### Cosa Nostra
Self-initiated · Design Systems
Case study: https://guilhermeribeiro.art/portfolio/cosanostra/

A complete design system in the Apple register — 34 documented components, three token layers, both themes drawn, and a governance section that says who gets to change it.

Twenty-four numbered sections carry it from colour and grid through to versioning. The library ships as specified components with props, states and dark mode rather than as a swatch sheet.

Tags: Design System, Tokens, Accessibility, Governance

### Magic Sprite
Self-initiated · 2026 · Design & Development
Case study: https://guilhermeribeiro.art/portfolio/magicsprite/
Live: https://magicsprite.netlify.app

A pixel art editor and animator that runs in the browser, which I designed and built for pixel artists and the game developers who use their sprites. The controls stay grey so the artwork is the only saturated colour on screen, and baking an animation keeps the original drawing.

About thirty thousand lines of TypeScript and CSS. It has bones with forward kinematics, a bake you can regenerate or undo, RotSprite rotation that adds no new colours, and sprite sheet export with the tags, origin and events a game engine reads.

Tags: Pixel Art, Animation, Creative Tools, Design & Code

### Axis
Product Designer
Case study: https://guilhermeribeiro.art/portfolio/axis/

Cement plant automation — quarry to dispatch on a single spine, so an operator moves along the process instead of between vendor screens.

Neutral grey carries all the structure. One pastel cyan carries meaning, and only three: a value under live control, the active navigation item, or a number that needs a decision. Nothing else is coloured.

Tags: Industrial, SCADA, Data Density, Dark UI

## Writings

Essays in Portuguese, published in full on the site.

### Desejo mimético e usabilidade
Ensaio · 2026 · pt-BR
Read: https://guilhermeribeiro.art/writings/desejo-mimetico/

Por que o usuário não consegue explicar o que quer, lido a partir de René Girard e de dois experimentos sobre contadores de popularidade.

Sobre roteiros de entrevista, componentes de prova social e convenções de interface que venceram pela cópia, como o menu hambúrguer e o gesto de puxar para atualizar.

### Comportamento humano e usabilidade
Ensaio · 2026 · pt-BR
Read: https://guilhermeribeiro.art/writings/comportamento-humano/

O que Norman, Nielsen e a psicologia experimental dizem sobre o corpo diante da tela: hábito, memória, atenção e o alcance do polegar.

Hebb e a repetição, Miller e Cowan sobre a memória, Fitts e Hick sobre o movimento, e o peso da estética na facilidade percebida.

### Manifesto cultural
Manifesto · 2026 · pt-BR
Read: https://guilhermeribeiro.art/writings/manifesto-cultural/

Contra a padronização da arte e a favor de voltar a fazer coisas bonitas, com Kant, Ortega y Gasset, Tarkovski, Fellini, Stan Brakhage e Walter Benjamin.

Um ensaio-manifesto em formato acadêmico, com uma parte dedicada ao cinema e nove compromissos para quem faz qualquer coisa que outras pessoas vão ver.

## Experience

- **CMO & Head of Product**, Reune Digital (PRESENT) — Owning product direction and marketing for the company — strategy, roadmap and team leadership, with design still in my own hands.
- **Product Designer**, Azape (2024 — 2025) — Design & UX strategy for published digital products and internal platforms across large-scale Brazilian companies.
- **UX/UI Designer**, Mamba Digital (2021 — 2022) — E-commerce UX powered by neuromarketing — flows, high-fidelity UI and a scalable component library.
- **UX/UI Designer**, Universidade Libertária (VOLUNTEER) — Volunteer work — designed a DAO mobile app and website from scratch with a team of three front-end developers.

## Capabilities

Self-assessed against shipped work on a five-step scale: 5 Lead (I set the standard here, and other people work to it.); 4 Advanced (Used repeatedly on shipped, paid work.); 3 Proficient (Shipped with it. I bring in a specialist for the deep end.); 2 Working (Enough to be useful, and to brief a specialist properly.); 1 Familiar (I can read it and work alongside it. I would not claim to own it.).

At level 5, Lead: Product Strategy, Product Discovery, Backlog & Prioritisation, Roadmapping, Scope Definition, User Research, Information Architecture, User Flows, Interviews & Surveys, Usability Testing, Design Systems, Design Tokens, Brand Identity, Prompt Engineering, AI-Assisted Delivery, Figma, Claude Code, CSS, Neuromarketing, Consumer Psychology.

Everything tracked: Product Strategy, Product Discovery, Backlog & Prioritisation, Roadmapping, Scope Definition, Continuous Discovery, Jobs to be Done, Stakeholder Alignment, Metrics & OKRs, Pricing & Packaging, Design Ops, Go-to-Market, User Research, Information Architecture, User Flows, Interviews & Surveys, Usability Testing, Service Design, Journey Mapping, Personas, User Stories, Card Sorting, Heuristic Evaluation, Accessibility, Design QA, A/B Testing, Design Systems, Design Tokens, Brand Identity, Component Libraries, Typography, Wireframing, Low to High Fidelity, Prototyping, Responsive Layout, Mockups, Data Visualisation, Desktop & Mobile, Motion Design, Micro-interactions, Prompt Engineering, AI-Assisted Delivery, AX Design, AI Product Design, Context Engineering, Agentic Workflows, Human-AI Interaction, Conversational Design, Evaluation & Guardrails, RAG & Retrieval, Multimodal Interfaces, Figma, Claude Code, Illustrator, Photoshop, Miro, Webflow, Framer, After Effects, InDesign, DaVinci, Adobe XD, CSS, React, JavaScript, Git & GitHub, Vite, SPAs, GSAP, Three.js & R3F, Python, Vue, Angular, TWIG, WebGL, Linux, Neuromarketing, Consumer Psychology, Cognitive Biases, Behavioural Economics, UX Writing, Decision Architecture, Copywriting, Data Science.

## Credentials

- Product Design — EBAC — Escola Britânica de Artes Criativas
- Fundamentals of Neuroscience — Harvard University
- Cognitive Psychology & Neuropsychology — University of Cambridge
- Consumer Neuroscience — Copenhagen Business School (2023)
- React JS — Complete Frontend Guide — Certification (2022)
- UX / UI Design — Google (2022)
- Complete Course in Interface Design — Certification (2022)
- B.Sc. System Analysis & Development — Universidade Cruzeiro do Sul (Ongoing)

## Contact

- Email: guilhermerfc.contato@gmail.com
- Phone: +55 (13) 99776-0984
- GitHub: https://github.com/sentidofront
- LinkedIn: https://linkedin.com/in/GuilhermeUX