Phantom Load

Definitions

System load that is real and costly but not obvious from the most visible usage patterns, often coming from retries, background work, duplicated events, or hidden traffic sources. In engineering slang, phantom load is what makes capacity planning feel haunted.
In plain English: Real system load coming from hidden or less obvious sources.
Example: "The team sized for user requests but missed the phantom load from retries, webhooks, and internal polling loops that quietly tripled real pressure."