In-app taxes

Case study

An end-to-end walkthrough of the product journey

Context and problem understanding

Microentrepreneurs in Brazil are required to pay the DAS tax monthly to keep their businesses compliant. Although the amount is fixed and the process is, in theory, simple, issuing the tax guide happens outside the banking environment, on government platforms or third-party apps that are commonly perceived as complex and unclear.

In practice, dealing with this payment involves low familiarity with tax topics, bureaucratic processes, and a strong fear of making mistakes. As a result, many entrepreneurs rely on accountants not because of technical complexity, but to delegate a process perceived as risky—even though it is operationally simple. In most cases, the work consisted of accessing the government website, issuing the DAS guide, and ensuring the payment was completed correctly.

The fear of becoming non-compliant led entrepreneurs to pay a high cost for this service, even though the DAS was created specifically to simplify tax obligations and reduce the need for intermediaries.

This scenario represented a clear opportunity for Nubank and was aligned with the company’s mission: reducing bureaucracy and complexity in financial services to empower people, while strengthening the role of the business account in the entrepreneur’s day-to-day financial life and introducing an innovative service. At the time, both government platforms and third-party apps only supported issuing the tax guide, requiring users to still access their bank separately to complete the payment.

From problem to approach

When I joined the project, the team already had clarity on the high-level problem and had started exploring possible solutions. As I reviewed existing research, analyzed the journey from the user’s perspective, and dug deeper into customer pain points, it became clear that the main risk was not usability alone, but trust.

Even with a functional flow, the solution would fail if users did not feel safe enough to stop using the government website or relying on an accountant. This insight redefined the project direction and became the foundation for all design decisions.

Based on this analysis, I proposed a shift in focus for the project. Instead of simply finalizing the existing experience, I redirected the work toward reducing cognitive load and fear of error, designing the journey around the user’s true job to be done: paying taxes correctly, in a simple, risk-free, and trustworthy way. The experience needed to clearly communicate what was being paid, when, and provide reassurance at every step.

Design decisions and scope framing

The journey was reduced to its essential steps, removing stages and information that did not directly contribute to generating and paying the DAS.

I consciously advocated for excluding edge cases that impacted a small portion of the user base, prioritizing a clear and safe solution for the majority of users and slicing the product into value-driven deliveries. These excluded cases would be addressed later. To support this decision, I requested data from business analysts to identify who truly composed the core audience and ensure the scope decisions were objective and data-informed.

I established simplicity and trust as the central decision criteria. Cognitive load, amount of copy, and reading pace were continuously calibrated to enable fast yet confident decisions, with optional depth available when needed. The goal was to find the optimal level of information.

I brought these decisions to discussions with product and engineering peers, clearly articulating the trade-offs involved, and aligned the direction with senior leadership stakeholders. With strong buy-in and positive feedback, we moved forward to the testing phase.

Testing and validation

Under my guidance and leadership, the solution was taken into usability testing using a high-fidelity MLP. I defined the study objectives, evaluation scenarios, and research briefing, as well as observed interviews and supported the team debrief.

The tests validated the main flow and revealed targeted improvements. At this stage, my role went beyond executing changes—I was responsible for deciding whether the experience had reached the required level of clarity and confidence to move into implementation, especially around payment confirmation moments. Improvements were incorporated quickly, keeping the focus on simplicity.

MVP and course correction

Speed to market was critical for the business. We identified that other banks and third-party solutions were attempting to address the same pain point, making first-mover advantage a strategic goal.

To enable this, we made deliberate scope cuts, focusing exclusively on DAS generation and payment, while postponing full tax management features to a later phase.

Due to a technical limitation, the MVP replaced the guide list with a manual month selection field and was released to 5% of the user base. Within a few days, we identified an error rate of approximately 40% in guide generation, mainly caused by confusion around the reference month.

This outcome reinforced a core principle I strongly believe in: simplicity of experience and cognitive load reduction. Instead of adding explanations or warnings, the solution needed to eliminate the possibility of error altogether.

Within one sprint, we returned to the original guide list approach, reducing the error rate to zero. At the same time, the early release allowed us to meet the strategic goal of being first to market.

Final reflection

This project reinforced the importance of treating sensitive moments in the user journey with absolute focus on clarity and confidence. In contexts where the cost of error is high, simplifying, reducing choices, and guiding users decisively creates more value than adding flexibility.

It was a deliberate exercise in scope framing, prioritization, and decision-making—balancing user needs, technical constraints, and business objectives.

made in Brazil