Email verification involves a number of processes. To complete each of them correctly and accurately would take time. There are a lot of things involved which makes it really hard to predict the exact or close time of completion.
As a very general guideline, our system process a list of 10,000 email addresses in less than 10 minutes but please don't quote us on this as you will see why this could differ by reading the information below.
Some of the factors that affect timing include...
1) Domain Frequency - If you have a lot of emails from the same ESP or provider (Eg. Lots of Gmail Addresses), its more time consuming to verify. This is because Gmail and many other ESPs have limits on how many connections it would accept from same IP address or network. If we exceed that, it would likely cause them to block us. This would only give us inaccurate data about those email addresses we are trying to verify.
2) Spam-Trap Addresses or Complainers - At date of writing this, we have local database of more than 365+ million spam-trap records and in excess of 120+ million complainer addresses. So for example, if you upload 10,000 email addresses...just to verify against our own local databases, it would have to scan each single record against nearly 40 million or more email addresses. Pretty mind boggling isn't it? Therefore, this could be a little time-consuming process if we want quality results.
3) Network Speed - This is highly unpredictable in any given environment. Sometimes, it's blazing fast speeds and sometimes its a little slower. In addition to this, add numerous amount of verification jobs that come through from 1000s of customers worldwide. So to manage it all, our engineers continually optimise our servers and network but there is very little we can do to speed it up even further. This also affects the speed of your verified results.
4) Large Lists - If you have uploaded a large list (Anything above 10,000 emails), we would have to make sure all is well before we start your verification job. These are often referred to as pre-validation checks. They include things like deduplication which involves verifying every single email address on your mailing list against every single other record on your list. Quite a tiresome process if you think about it. Despite the complexity, our system handles it quite well. It does most jobs within seconds and prepares the files for verification.
5) Miscellaneous - With technology, there are quadrillion things that are involved. There are quite a lot of other reasons why your verification job might be taking time. To list everything involved down here would not only be a waste of time but also pointless to users because most of it cannot be put into simple understandable language.
Just rest assured that our team will be doing everything in their power to get your verification job processed as soon as we can.