What caused the sudden spike in failed API calls for M2P Fintech's virtual card creation service yesterday afternoon?

Introduction

The sudden spike in failed API calls for M2P Fintech's virtual card creation service yesterday afternoon is a critical issue that demands immediate attention and thorough analysis. As we delve into this problem, we'll employ a systematic approach to identify, validate, and address the root cause while considering both short-term fixes and long-term strategic implications.

Step 1

Clarifying Questions (3 minutes)

• Looking at the timing, I'm thinking this could be related to a recent deployment. Has there been any recent code push or system update in the last 24-48 hours?

Why it matters: Recent changes are often culprits in sudden performance issues. Expected answer: Yes, there was a minor update to the API gateway. Impact on approach: If confirmed, we'd focus on rollback options and code review.

• Considering the specificity of the issue, I'm wondering about the scope. Is this affecting all virtual card creation requests or only a specific subset of users or card types?

Why it matters: Helps narrow down potential causes and affected user segments. Expected answer: It's affecting about 60% of all virtual card creation requests. Impact on approach: We'd investigate common factors among the affected requests.

• Given the critical nature of fintech services, I'm curious about our monitoring systems. Did our alert systems catch this issue immediately, or was it reported by users first?

Why it matters: Assesses the effectiveness of our monitoring and incident response. Expected answer: The alert system flagged the issue within 10 minutes of onset. Impact on approach: If delayed, we'd prioritize improving our monitoring thresholds.

• Considering potential external factors, have there been any reported issues with our payment processing partners or card networks in the last 24 hours?

Why it matters: Rules out external dependencies as potential causes. Expected answer: No reported issues from our partners or card networks. Impact on approach: If issues reported, we'd coordinate with partners for resolution.