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.

Experience

4+ years Product Design

Background

Automation Engineering

Tools

Figma · FigJam · Claude · GitHub

Areas of focus

Onboarding & Conversion

Account-opening and registration flows for high-stakes contexts: fintech, financial inclusion, underbanked demographics. The job is to collect what the system needs without making the user feel like they're filing paperwork.

Designing account-opening and

registration flows that reduce friction without sacrificing security or data quality. Experience with high-stakes demographic contexts (financial

inclusion, underbanked segments).

Onboarding

Conversion

Fintech

Authentication & Identity

Login, MFA, and identity verification flows that don't make users feel like suspects. Hands-on work with Keycloak-based systems, OAuth/OIDC flows, and the UX of security-conscious products where friction has a cost.

Designing login, MFA, and identity verification flows that balance security requirements with usability. Hands-on experience with Keycloak-based authentication systems and

OAuth/OIDC flow design.

Auth UX

Keycloak

MFA

Security

Accessibility

WCAG 2.1 certified. I design for accessibility from the first decision: contrast ratios, touch target sizes, keyboard navigation, screen reader compatibility, and accessible error handling. Not as an afterthought at the audit stage.

WCAG 2.1 certified. I design for

accessibility from the first decision, not the audit. Experience with colour contrast, touch target sizing, keyboard navigation, screen reader compatibility, and accessible error handling.

WCAG 2.1

A11y

Inclusive design

Design Systems

Building and maintaining component libraries that developers can actually use: clear naming, documented states, useful constraints. I've collaborated with design system teams during product redesigns and contributed new components back to shared libraries.

Building and evolving component

libraries that scale. Experience

collaborating with design system

teams during product redesigns,

ensuring new components align with system constraints and contribute back to shared libraries.

Components

Tokens

Figma

UX Research & Strategy

User interviews, competitive analysis, co-creation workshops, usability testing, impact-effort prioritisation. I use research to make trade-off decisions visible, not to justify decisions that were already made.

End-to-end research: user interviews, competitive analysis, co-creation workshops, usability testing, and impact-effort prioritisation. I use research to make trade-off decisions visible, not to justify decisions already made.

User interviews

Benchmarking

Prioritisation

AI-Augmented Workflows

Built open-source AI skills for Claude covering UX auditing, critique, discovery, strategic design, and frontend specification. Interested in where AI increases rigour in the design process, not where it just generates faster output.

Built open-source AI tools for

structured UX work — auditing,

critique, discovery, and specification. Interested in where AI can increase rigour and transparency in the design process rather than replacing judgment with automation.

AI tooling

Open source

Claude

How I work

Function before aesthetics

The order is fixed: task completion first, then clarity, accessibility, feedback, efficiency, consistency. Aesthetics come after all of that. This isn't a position I hold. It's the only ordering that produces work I'd put my name on.

The hierarchy is fixed: can the user complete the task? Is it clear? Is it accessible? Does it give feedback? Is it efficient? Is it consistent? Aesthetics come after all of that — not instead of any of it.

Constraints as tools

I document why decisions were made: what was cut, what was deferred, what the trade-off was. A handoff spec without reasoning is a spec that generates questions in every sprint review and gets quietly overridden.

Technical constraints, timeline constraints, business

constraints — these are design inputs, not obstacles. The best solutions in my work have usually come from working within a real constraint rather than designing around it.

Decisions documented

Timeline, technical, business: constraints are design inputs. The best decisions in my work have usually come from working within a real constraint, not from designing in a vacuum and hoping implementation follows.

I document why decisions were made, not just what was decided. That includes what was cut, what was deferred, and what trade-offs were made. A handoff spec that doesn't explain the reasoning is a spec that will generate questions in every sprint review.

Cross-functional by default

I've been the only designer in a team of engineers and a designer embedded in a larger product org. Both contexts need the same thing: everyone in the room agreeing on what problem they're solving before anyone touches a tool.

I've worked as the only designer in a team of engineers, and as a designer embedded in a larger product org. Both contexts require the same thing: shared understanding of what problem is being solved and why the chosen solution addresses it.

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