Why has Messenger API webhook delivery success rate dropped to 65%?

Introduction

The sudden drop in Messenger API webhook delivery success rate to 65% is a critical issue that demands immediate attention. This significant decrease in performance could have far-reaching consequences for user experience, platform reliability, and overall business metrics. I'll approach this problem 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)

• Looking at the timing, I'm thinking there might be a recent change that triggered this. Has there been any significant update to the Messenger API or related systems in the past week?

Why it matters: Recent changes often correlate with performance issues. Expected answer: Yes, there was a minor update to the API. Impact on approach: If confirmed, we'd focus on the recent change as a primary suspect.

• Considering the scale of the issue, I'm wondering about its distribution. Is this 65% success rate consistent across all users and regions, or are there noticeable patterns?

Why it matters: Uneven distribution could point to specific infrastructure or regional issues. Expected answer: The issue is more pronounced in certain regions. Impact on approach: We'd prioritize investigating region-specific factors if confirmed.

• Given the nature of webhooks, I'm curious about the failure modes. Are we seeing timeouts, connection errors, or specific error codes in the failed deliveries?

Why it matters: Different error types suggest different root causes. Expected answer: There's a mix of timeouts and connection errors. Impact on approach: This would guide our technical investigation towards network and server capacity issues.

• Thinking about potential external factors, have there been any significant changes in usage patterns or volume of webhook calls recently?

Why it matters: Sudden spikes in usage could overwhelm the system. Expected answer: Usage has been relatively stable. Impact on approach: If confirmed, we'd focus more on internal system issues rather than external pressures.

• Considering the possibility of measurement errors, has there been any change to how we track or calculate the webhook delivery success rate?

Why it matters: Ensures we're not chasing a phantom problem due to faulty metrics. Expected answer: No changes to the measurement system. Impact on approach: Confirms we should focus on actual delivery issues rather than metric calculation problems.