Node.js polling loop cost client $3,000 in AWS bills

Short summary

A Node.js polling loop with no backoff strategy caused a startup's AWS bill to jump from $200 to $3,000/month by repeatedly querying the database when idle. The fix was adding a 5-second delay between queries or switching to event-driven architecture. Key lesson: monitor idle-state behavior, define backoff for all polling, and track infrastructure costs alongside performance metrics.

• •Unbackoffed polling loop triggered 100k+ database queries daily when queue was empty
• •Cost ballooned from $200 to $3,000/month due to wasted database, network, and CPU resources
• •Fix: add backoff delay or replace polling with event-driven message queue design

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