Searchbug Tech FAQ: How Our Reachable Phone Number Service Works

Recently, a Searchbug customer had a question about how we checked whether phone numbers were active or inactive.

The customer had processed a large quantity of phone numbers with our Standard Reachable Number Service. Many of the numbers were shown as active.

Our customer then provided our active/inactive number testing system with two phone numbers. He had already called both numbers to ensure they were inactive.

One phone number gave an invalid number recording. The other number answered with a “call rejected” notice.

Naturally, our customer was concerned about the efficacy of our active/inactive number testing system. So they asked about how our Reachable Phone Number Service works.

Andre Polakoff, our CTO explains:

How the Searchbug Reachable Phone Number Service Works

The Standard Reachable Phone Number Service relies on call detail record (CDR) logs from major carriers.

CDR logs are the records produced by telephone carrier telecommunications equipment whenever a phone call is transmitted through the carrier’s hardware. CDR logs include call attributes such as the call duration, source number, destination number, and whether or not the call was completed.

Searchbug uses algorithms to evaluate multiple factors from the CDR logs and determine if a number is active or inactive.

A phone number is considered inactive when a call to that number returns a “not found” response and there were no successful calls made to that number since it was checked.

The number is still considered active if the response is “rejected,” “declined,” “not accepted,” etc. Technical issues or settings to actively block incoming calls likely render these numbers unreachable when they are checked.

A number is also considered inactive if technical issues persist for 60 days. But a number is reported as active if it’s been freshly rejected/blocked.

It’s possible that some inactive numbers are reported as active if:

• The number became inactive recently (within the last two weeks).
• The user recently blocked the number or technical issues started.
• The number is inactive, but it wasn’t dialed in the last 60 days (not in the call detail record logs).

This method—although not 100% accurate—is very affordable, fast, and can be used on a 24/7 basis.

We also offer an Advanced Reachable Number Service.

The Advanced Reachable Number Service performs a real-time check of carrier billing systems. We use other methods when the line status can’t be obtained from the carrier records. This includes automated calls to numbers on your list.

The Advanced Reachable Number Service is 100% accurate. But, the advanced service takes more time than the standard service. The Advanced Reachable Number Service is also only available from 8AM to 6PM PST. Since numbers are actually dialed, we don’t want to call people at inappropriate hours.

This way, Searchbug customers can choose between a fast and affordable scan, and a reliable, but more expensive, line status verification.

Check out our Reachable Phone Number Batch Service if you need numbers verified or want to see how it works for yourself.