João Calixto.
Product Designer.
I design the parts of a product that users only notice when they're broken: onboarding flows, authentication, registration, the moments where someone decides whether to trust what they're using.
BACKGROUND
I started in software engineering. What kept pulling me toward design wasn't a change of interest. It was the same problem appearing everywhere: systems that worked fine technically but failed the people using them. Gaps between what a product could do and what users could actually understand it was doing.
That gap is still what I work on. The engineering background shapes how I collaborate: I know what "backend constraint" actually means during a sprint review, I've reviewed PRs, and I've sat through enough implementation sessions to know exactly where design decisions get lost in translation. When I say something isn't feasible to ship this sprint, I know why.
I've worked on Keycloak-based authentication systems, which taught me that security requirements and usability requirements aren't opposites. They're a constraint that takes real craft to resolve without sacrificing either. I've designed onboarding flows for underbanked demographics in Brazil, where shared devices, spotty connectivity, and limited digital literacy aren't edge cases. They're the baseline.
Accessibility is where I find the clearest design problems. When you design for someone using a screen reader, or with a motor impairment, or on a 2G connection, every ambiguous decision has to become explicit. The constraints force the work to be cleaner. That turns out to be better for everyone, not as a principle, but as a practical outcome you can see in the finished product.
In 2026 I open-sourced five AI skills for Claude: UX auditing, design critique, structured discovery, strategic design, and frontend specification. I built them because I was frustrated with AI feedback that sounded authoritative but wasn't grounded in anything. Each skill labels what's data, what's estimated, and what's an inference. They're on GitHub.
Areas of focus
Onboarding & Conversion
Onboarding
Conversion
Fintech
Authentication & Identity
Auth UX
Keycloak
MFA
Security
Accessibility
WCAG 2.1
A11y
Inclusive design
Design Systems
Components
Tokens
Figma
UX Research & Strategy
User interviews
Benchmarking
Prioritisation
AI-Augmented Workflows
AI tooling
Open source
Claude
How I work
Function before aesthetics
Constraints as tools
Decisions documented
Cross-functional by default
Certifications
Scrum.org
Professional Scrum with User Experience I (PSU-I)
Ross Mullen
Introduction to Web Accessibility WCAG 2.1
Rob Sutcliffe
Master Digital Product Design: UX Research & UI Design
Microsoft
Responsible Prompting for Business: Unlocking the Power of AI


