Author: Maristela Calazans

When people open the Nubank app, they see a clean interface and a straightforward path to manage their money. What they don’t see is the operational and architectural complexity required to deliver that experience consistently across Brazil, Mexico, and Colombia — under different regulatory regimes, connectivity realities, device constraints, and economic contexts.

As a Nubanker working closely with product teams across markets, I’ve learned that simplicity at scale is not a design preference. It’s a strategic decision. And it requires deliberate trade-offs in architecture, product strategy, and culture.

Here are five lessons that shaped how we build and scale simple experiences for 127 million customers as one of the largest digital financial services platforms in the world.

1. Empathy must be operationalized, not just measured

Dashboards tell us what is happening, but they rarely explain why. For global product teams, especially when working across different countries, it’s easy to design based on assumptions formed inside high-bandwidth office environments. But our customers don’t operate in those conditions.

That’s why we institutionalized initiatives like Customer Connection, where every quarter teams step outside the office to observe real-life usage scenarios. I’ve visited places like 25 de Março in São Paulo, a crowded commercial district where transactions happen under unstable internet, older devices, and real-world pressure, to see how people are making payments, buying things, and how they’re spending their money. 

This isn’t a field trip; it’s a reality check. Seeing a product fail in the wild tangibilizes pain points that a data point simply can’t capture, ensuring engineers and Product Managers (PMs) build for the street, not the lab. In the end, what looks like a “simple Pix flow” in staging can behave very differently in that environment.

For those who work with Product, this is critical: qualitative immersion surfaces constraints that analytics cannot detect. It changes prioritization. It influences performance budgets. It reshapes assumptions about reliability. If you don’t see your product under stress, you risk optimizing for ideal conditions instead of reality.

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2. The real risk is accumulated friction

The most dangerous threats to customer loyalty aren’t the catastrophic system failures that trigger support calls. They are the silent frictions, the tiny, nagging glitches that a user won’t bother to report but will eventually grow to resent. But each minor frustration accumulates, what we often call internally a “death by a thousand paper cuts.”

To solve this, product leaders must adopt the mindset of the “first and most annoying” tester. This requires a culture where PMs use their own products relentlessly to catch friction while it is still minor, before it becomes obvious enough pain for a customer to abandon the brand. If the product team isn’t identifying every tiny hurdle in the daily journey, they’re effectively forcing the customer to do the quality assurance work for them.

I often ask teams: “Are we discovering friction before customers feel it, or only after metrics decline?”. The difference defines whether you are leading product quality or reacting to it.

3. Simplicity requires ruthless choice architecture

In fintech, complexity is abundant by default. Funds, liquidity options, risk profiles, transfer methods, compliance layers: the system wants to expose everything, but the customers don’t.

Take the Caixinhas feature. Technically, the platform could offer a dozen investment funds with varying liquidity and risk profiles. However, Nubank realized that providing too many options prevents the very thing the customer actually wants: building a financial habit. By reducing the flow to a 2-3 step process, they hide the rail, the technical complexity of fund selection, to focus on the Job to be Done (JTBD).

Whether a user is paying a bill via the Assistant or saving for a goal, they don’t care about the technical format but about the outcome. By guiding the user with intelligent defaults rather than a menu of complexity, the product fosters financial health through ease of use.

4. Global core, local nuance

Scaling to 127 million customers across different borders requires a strategy of platformization. Instead of building separate apps for each country, Nubank develops global modules that can be adapted with local nuances. This strategic blueprint allowed them to launch Bre-B (the Colombian equivalent of the Brazilian Pix) six months faster than previous regional expansions.

This 6-month advantage is the primary ROI of thinking globally from day one. The framework follows a strict Global Core vs. Local Nuance logic:

  • Global Core: The universal “Jobs to be Done”; receiving, transferring, and saving money.
  • Local Nuance:
    • Regulatory limits: Adapting transfer caps mandated by different central banks.
    • “Modo Rua” (Street Mode): A Brazil-specific security feature triggered by local urban realities like phone theft.
    • Cash-in locations: Integrating physical store partnerships in Mexico, where the economy remains heavily reliant on paper money.

By building on a global platform, the team avoids the technical debt of maintaining three different versions of the same code, allowing for rapid innovation at scale.

5. Product intuition is built from repertoire

Product excellence is half science and half art. While frameworks and technical manuals provide the foundation,repertoire is what ultimately drives intuition. A highly successful PM at Nubank who has a background in Art History and Education as evidence that curiosity and multi-faceted humanity are more valuable than a purely technical pedigree.

I own a diverse repertoire—spanning Chemistry, Military service, Gastronomy, Perfumery, and Piano—, reflecting this philosophy. Innovation requires the ability to see the product through the lens of human behavior. Understanding why a person feels anxiety over a payment or pride in saving is an exercise in human-centricity that a background in humanities often prepares a person for better than a coding bootcamp.

If we treat a product purely as a technical optimization problem, we miss the human layer. 

Simplicity at scale is never accidental

As Nubank scales toward even greater heights, the challenge becomes managing intelligent friction. In finance, simplicity cannot come at the cost of security; sometimes, the app should slow the user down, like a security prompt for a large unusual transaction, to provide value-added friction that protects their life savings.

The ultimate question for any product leader is this: Are you outsourcing your company’s complexity to the customer, or are you doing the hard work of hiding the machinery to create magic?

Technology’s only job is to return time and power to the people.

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