Nubank Engineering Meetup #9, themed “Platform in Focus,” was an event that brought together engineers, tech leaders, and enthusiasts to explore the latest trends and challenges in platform engineering, observability, and mobile development. 

Over the course of nearly two hours, the meetup covered a wide range of topics, from the strategic importance of observability to the technical intricacies of scaling a large-scale mobile app. Attendees gained insights into how Nubank is tackling these challenges, with discussions on automation, server-driven UI frameworks, phased release strategies, and the role of AI in observability.

This blog post provides a comprehensive summary of the event, highlighting key discussions, practical insights, and actionable takeaways. Whether you’re an engineer, a tech leader, or simply curious about how Nubank is innovating in the tech space, this recap offers a detailed look at the topics covered during the meetup.

Observability: The foundation of modern platforms

The first major discussion centered on observability—a concept that goes beyond traditional monitoring to provide deeper insights into system behavior and performance.

The evolution of Observability

The discussion traced the evolution of observability, comparing it to telemetry in motorsports, particularly Formula 1. Just as Formula 1 cars use hundreds of sensors to collect real-time data, observability in software systems enables teams to monitor, analyze, and respond to issues quickly.

The conversation highlighted how observability has shifted from a focus on logs, metrics, and alerts to a more holistic approach that combines data, people, processes, and tools. This shift allows teams to not only detect failures but also understand their impact on the business.

The business case for Observability

Observability was framed as a strategic investment rather than a cost. Poorly implemented observability can lead to wasted resources, such as excessive logging that generates unnecessary data. On the other hand, a well-designed observability strategy can significantly reduce Mean Time to Recovery (MTTR) and improve system reliability.

The discussion also emphasized that observability requires a cultural shift. Teams must prioritize understanding the business context and the impact of their systems on end-users. Tools alone are not enough; they must be complemented by strong processes and a focus on collaboration.

Observability in practice

Practical tips for building an observability platform were shared, including:

  • Start small: Focus on specific pain points and gradually expand.
  • Understand the business: Know the impact of failures on revenue and customer experience.
  • Collaborate: Build partnerships across teams to ensure alignment.
  • Automate wisely: Automating flawed processes can amplify problems.

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Scaling Mobile Engineering at Nubank

The second half of the meetup focused on the challenges and solutions involved in scaling mobile engineering at Nubank.

The complexity of scaling Mobile

Nubank’s mobile app is the primary interface for millions of customers, making it a critical component of the company’s success. However, scaling mobile development comes with unique challenges:

  • A monorepo structure with multiple programming languages (Java, Kotlin, Swift, Flutter).
  • Over 2,000 engineers contributing to the app, resulting in more than 100 pull requests per week.
  • The need to balance rapid feature development with system stability.

Automating the developer experience

To manage this complexity, Nubank’s Mobile Platform Team has built a suite of tools and processes to streamline development:

  • Automated setup: New engineers can get their development environment up and running in about an hour using a CLI tool.
  • Dynamic CI/CD pipelines: Tests and validations are run specific to each pull request, reducing build times.
  • BORS: A tool for managing high volumes of pull requests, ensuring that the main branch is always up-to-date.

Backend-Driven Content (BDC)

One of the most innovative solutions discussed was Backend-Driven Content (BDC), a server-driven UI framework that allows the backend to control the app’s interface. This approach decouples the app’s UI from its binary, enabling faster feature rollouts and real-time adjustments.

The discussion highlighted how BDC reduces dependency on app updates, which can take weeks to reach all customers due to app store approval processes and user adoption rates. With BDC, teams can deploy changes directly to the backend, making them available to users instantly.

Release strategy and Observability

Nubank’s phased release strategy was also explained:

  • Alpha: Internal releases for engineering teams.
  • Beta: Controlled releases for employees and beta testers.
  • Production: Gradual rollout to all customers, starting with 5% and scaling to 100% over several days.

Throughout this process, observability tools like OpenTelemetry and Sentry are used to monitor app performance and detect issues early. Alerts are routed to the appropriate teams using Opsgenie, ensuring quick resolution of problems.

Security and AI in Observability

The meetup also touched on two critical topics: security and the role of AI in observability.

Security in Mobile Development

Nubank’s approach to mobile security includes mechanisms like certificate pinning and device integrity checks to protect user data. The discussion emphasized the importance of staying ahead of threats like malware and keyloggers, particularly in a financial services context.

AI and Observability

The potential of AI in observability was explored, with a focus on its ability to accelerate problem-solving and predictive analytics. However, the discussion also highlighted the risks of adopting AI without a solid foundation. AI tools rely on high-quality data and well-defined processes to deliver value. Without these, AI can lead to misleading conclusions and wasted resources.

Design System and unified developer experience

Another key topic was the importance of a Design System in creating a unified developer experience. The discussion highlighted how Nubank’s Design System standardizes components, making it easier for engineers to build consistent and scalable features. The Design System also embeds analytics, enabling teams to track user interactions and gather valuable insights.

The conversation also touched on the role of Developer Experience (DevEx) in improving productivity and collaboration. By providing tools and frameworks that abstract complexity, Nubank enables engineers to focus on building features rather than managing infrastructure.

Key takeaways

  • Observability is a strategic priority: It’s not just about monitoring systems but understanding their impact on the business.
  • Automation is key to scaling: Tools like BORS, dynamic CI/CD pipelines, and BDC enable Nubank to manage complexity and deliver features faster.
  • Collaboration drives innovation: Building a strong engineering community, both internally and externally, is essential for solving complex problems.
  • Security and AI are critical: As systems grow more complex, ensuring their security and leveraging AI responsibly will become increasingly important.

Join the conversation and stay connected

Nubank Engineering Meetup #9 was a testament to the company’s commitment to innovation and collaboration. By sharing their experiences and challenges, the speakers provided valuable insights into how platform engineering and observability are shaping the future of tech.

For those who missed the event, the recording will be available on Nubank’s YouTube channel. Stay tuned for more updates and join the conversation on LinkedIn! 

Whether you’re an engineer, a tech leader, or simply passionate about innovation, Nubank’s engineering meetups offer a wealth of knowledge and inspiration. Don’t miss out on future events—connect with Nubank’s tech community today!

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