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A reserved RingPool number is a number set aside for attribution tracking that only activates once all pooling numbers are in use.
Reserved RingPool numbers are used for attribution tracking only if all “Pooling” phone numbers are in use when a number is requested. Numbers are only marked as reserved if a RingPool hasn’t presented an overflow number in at least 30 days. The percentage set aside for reservation is configured at the network level. Each night, the least recently called phone numbers are marked “Reserved” if the RingPool is eligible to be downscaled. Reserved RingPool numbers won’t connect when dialed as a test, since the number isn’t actually active. If a Reserved number goes on to meet the criteria for an unused number, it’s removed from the RingPool on the last day of the month — see RingPools Sizing Logic for the exact removal criteria. A Reserved number that gets called back into active service before then returns to Pooling status instead. Applies to: RingPool numbers marked “Reserved.”

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Last modified on September 25, 2026