Invalidating a Marketplace Hypothesis with a Growth Experiment – Lojinha Z1

About Z1

Z1 is a Brazilian neobank designed for teenagers, offering services like prepaid credit cards, fee-free digital accounts, Pix payments, savings accounts, and  gift card purchases and top-ups.

• Startup
• Brazil
• B2C fintech
• Near 1M users 
• 2021 

The Challenge

As a rapidly growing startup, Z1 constantly sought innovative ways to drive growth, generate new revenue streams, and increase user engagement.

The Goal

• Increase average time spent within the app.
• Increase user TPV (Total Processing Volume) and CLTV (Customer Lifetime Value).
• Establish clear paths to monetization and revenue generation.

The Hypothesis

Following the successful launch of Banca Z1 (in-app gift card purchases), leadership identified a potential opportunity in the growing Gen Z trend of buying and selling handmade and thrifted items. This led to the idea of “Lojinha Z1” (lojinha translates to “little shop”), an in-app marketplace where users could buy and sell items using their Z1 accounts.

My Role

As a Product Manager, designing and leading the experiment, my focus was on validating the marketplace concept through a structured experiment:

• Problem Definition, Hypothesis & Experiment Roadmap: While the marketplace idea was intriguing, I wanted to ensure the solution addressed both business needs and user value. Partnering with the design team, I defined clear problem statements for both potential buyers and sellers within the app. These problem statements served as the foundation for developing testable hypotheses and a structured experiment roadmap.

• Key Metric Definition & Monitoring: I identified and tracked key metrics to evaluate the experiment’s success. These included the number of users engaging with “sell here” prompts, the number of users interacting with marketplace entry points (“fakedoors”), engagement rates with promotional communications, and conversion rates.

• Scope Definition & Development Management: Since the development team was accustomed to building full features, I encouraged a shift towards an experimentation mindset. I defined a minimal scope for the experiment, focusing only on the core elements needed to gather data from a 1% user base.
• Launch, Reporting, & Stakeholder Alignment: I managed the execution of the experiment, regularly reporting results and next steps to the founders and key stakeholders, ensuring continuous alignment and informed decision-making.

Results and Impact

The rapid experimentation generated data-driven insights:

• Agile Execution: The experiment was designed, developed, and executed within a rapid four-week timeframe, demonstrating an agile approach to product development.
• Modest Engagement Increase: The experiment resulted in a 0.5% increase in average time spent within the app.

Key Learnings

While the marketplace concept held promise, the experiment revealed that achieving significant increases in user TPV, CLTV, and new revenue streams would require substantial investment and resources. At that stage in Z1’s growth, pursuing this direction wasn’t scalable or the most effective use of limited resources. Despite not moving forward with a full marketplace build, the Lojinha Z1 experiment successfully instilled an experimental and agile mindset within the development teamto validating assumptions and prioritizing resources, paving the way for future data-driven product development initiatives.

Team (with much appreciation for their hard work): Ana Helena, Jonathas Souza, and Natalia Albertone.