Tributo fácil
Tributo Fácil is a mobile app that simplifies tax payment and property management for citizens of Cubatão and Vinhedo.
overview
I remember staring at the old interface thinking, this app deserved better than resignation…
Despite its utility, the app suffered from low adoption caused by an outdated interface, poor usability, and a lack of user trust. Many users preferred paying at lottery agencies, leading to long queues and inefficiencies.
Our team was tasked with a complete redesign focusing on enhancing credibility and ease of use while working within legacy back-end constraints.
Sucess criteria
Success was defined by specific KPIs:
Increase in task success rates.
Monthly active user growth.
User satisfaction and trust.
Additionally, reducing reliance on physical payment locations was a key goal.
TEAM
ROLE
Lead Designer
INDUSTRY
TIMELINE
1.5 year
Ideation
In my ideation process, I conducted multiple rounds of iterative testing and speed-dating sessions.
Benchmarking against financial and govtech apps helped establish design standards and best practices.
I carried out sustained research across the entire project, including month-long diary study, market research, and additional investigations that directly informed key business decisions and ensured the app’s features and design aligned with the needs of its intended audience.
App redesign
Together with 2 amazing designers colleagues, we rebuilt the entire application end-to-end, enhancing its core functionality and user experience, restructuring the information architecture for intuitive navigation, and delivering a cohesive, contemporary UI.
Furthermore, I found that shared understanding is more valuable than shared tools. Collaborating with the client’s engineering team:
Improved their UX maturity.
I provided training and workshops so UX principles and methodologies become familiar.
Testing cycles
Two rounds of usability testing (remote and in-person) with over +40 users validated improvements.
Testing confirmed increased clarity and trust, with task success rising.
Users praised the clear progress indicators and confirmation messages.
"It's unbelievable to be able to do in minutes something that I used to have to leave work early to do in person at an agency."
— Patrícia Lopes, 37
"The system is so much cleaner and more user-friendly! All the information is clearly presented to me."
— Maurício, 54
Seeing users finally relax into the interface was its own reward.
93%
Task success rate
77% increase
Retention rate
26%
MAU
20.000 downloads
First Q3
In conclusion…
This project reinforced the importance of designing for trust in digital financial environments.
By prioritizing clarity, transparency, and consistent feedback, we reduced user hesitation and enabled smoother, more confident interactions.
Working within legacy constraints required careful decision-making and incremental improvement, demonstrating that meaningful progress can happen without full system overhauls.