What's causing the sudden increase in failed Verve card authentications through Interswitch over the past 24 hours?

Introduction

The sudden increase in failed Verve card authentications through Interswitch over the past 24 hours is a critical issue that demands immediate attention. This analysis will systematically identify, validate, and address the root cause while considering both short-term fixes and long-term implications for our payment processing system.

I'll approach this problem by first clarifying the context, then ruling out external factors before diving deep into our product ecosystem, user journey, and relevant metrics. We'll generate data-driven hypotheses, conduct root cause analysis, and develop a comprehensive plan for validation and resolution.

Step 1

Clarifying Questions (3 minutes)

• Looking at the timing, I'm thinking this could be related to a recent system update. Have there been any changes to our authentication system or Interswitch integration in the last 48 hours?

Why it matters: Recent changes often correlate with sudden performance shifts. Expected answer: Yes, a minor update was pushed yesterday. Impact on approach: If true, we'd focus on rollback options and code review.

• Considering the scope, I'm wondering if this is affecting all Verve card users or a specific segment. Can you provide data on the user segments experiencing these failures?

Why it matters: Helps narrow down potential causes and affected user base. Expected answer: It's affecting about 60% of Verve card users, across various segments. Impact on approach: If widespread, we'd look at system-wide issues rather than user-specific problems.

• Given the critical nature of authentication, I'm curious about our current failure rate. What's the normal authentication failure rate for Verve cards, and what are we seeing now?

Why it matters: Establishes the severity of the issue and baseline for comparison. Expected answer: Normal rate is 2-3%, current rate is 15-20%. Impact on approach: A significant increase would prioritize this as a high-severity incident.

• Thinking about potential external factors, has Interswitch reported any issues on their end or changes to their API in the last 24 hours?

Why it matters: Rules out or includes partner-side issues. Expected answer: No reported issues from Interswitch. Impact on approach: If no issues reported, we'd focus more on our internal systems and integration points.