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What Happens When the External System Fails?

Type: Structure
Category: Async
Audience: Engineers integrating with third-party systems, APIs, or partner platforms

🔍 What This Perspective Asks

  • What exactly happens if an external system goes down?
  • Is the failure detected, logged, and degraded gracefully?
  • Who gets hurt—and how much?

⚠️ Common Failures

  • Partner API goes down → internal queues fill silently
  • Retry storms → overload own systems
  • UX degrades (empty dashboards, broken buttons) with no user messaging
  • Errors silently swallowed because “async = eventually”

✅ Better Failure Handling

  • Explicit fallbacks or UI states when partner APIs fail
  • Timeout and retry policies per integration—not global
  • Queue isolation for high-risk dependencies
  • Alert on external system latency/spike—not just failure
  • Document UX impact and expected behavior per integration

🧠 Core Principle

Async doesn’t mean ignore the failure.
It means control how the failure manifests.

❓ FAQ

  • Q: We have retries. Isn’t that enough?
    A: Not if the user or system can’t tell what happened.

  • Q: Should we surface all integration failures?
    A: No. But you should choose who needs to know what—and when.