What's causing the sudden increase in failed transactions on the Lunar card in Germany?

Introduction

The sudden increase in failed transactions on the Lunar card in Germany is a critical issue that demands immediate attention. This problem directly impacts our users' ability to make purchases, potentially damaging trust in our product and affecting our bottom line. I'll approach this analysis systematically, focusing on identifying the root cause, validating hypotheses, and developing both short-term fixes and long-term solutions.

Step 1

Clarifying Questions (3 minutes)

• Given the specificity to Germany, I'm wondering about localized factors. Has there been any recent change in German financial regulations or banking systems?

Why it matters: Regulatory changes could directly impact transaction processing. Expected answer: No significant regulatory changes recently. Impact on approach: If true, we'd focus more on internal or technical issues.

• Considering the term "sudden," I'm curious about the timeframe. When exactly did we start noticing this increase in failed transactions?

Why it matters: The timing could correlate with specific events or changes. Expected answer: The issue started about a week ago. Impact on approach: Recent timing would narrow our focus to recent changes or events.

• Looking at user segments, I'm thinking about potential patterns. Are these failed transactions concentrated among specific user groups or transaction types?

Why it matters: Identifying patterns could point to specific issues affecting certain users or use cases. Expected answer: It's affecting all user groups fairly evenly. Impact on approach: If true, we'd look at more systemic issues rather than user-specific problems.

• Considering our systems, I'm wondering about our monitoring setup. Have there been any recent changes to how we measure or define failed transactions?

Why it matters: Changes in measurement could create a false perception of increased failures. Expected answer: No recent changes to measurement systems. Impact on approach: If confirmed, we'd focus on actual transaction failures rather than measurement issues.

• Thinking about recent updates, I'm curious if we've rolled out any new features or backend changes recently, particularly in Germany?

Why it matters: Recent changes could have unintended consequences affecting transactions. Expected answer: A minor update was pushed last week. Impact on approach: If true, we'd prioritize investigating that update's potential impact.