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How is EV3 different from EV2?

EV3 was developed with a newer framework that supports REST and JSON. The EV3 service builds on top of the core features of the EV2 service and improves overall performance, accuracy and usability. The added logic greatly improves on the service's ability to establish real-time communication with host servers to verify email addresses. Many mail servers are now configured to handle mail communication with extreme prejudice, and they employ various tactics in order to try and reduce spam and phishing bots from getting any information past them. As a result, normal SMTP verification techniques are becoming less reliable. EV3 is smart enough to not just recognize these techniques, but to also anticipate them so that they don't get in the way of the verification process.

Like EV2, the system has background processes that are constantly gathering information. If we were not able to get a piece of information on the first request, it is likely a background process will obtain it and have it ready for you next time. EV3 combines all the functionality of its predecessor and more into just two new operations. For example, email cleaning and correction is now included as part of the standard set of procedures in each operation.

I ran the same email twice. The second request returned SMTP level information but the first time it did not. What happened?

Our system has background processes that constantly monitor new requests. We did not have the information on the first request, but the background process saw the request, and gathered the information so that it was instantly available the next time you requested it.

I have a bunch of emails that I absolutely must have the SMTP level information for, what should I do?

You should run them first against our ValidateEmailAddress operation. Then wait an hour or so and take the ones that had unknown values in the SMTP level checks and run them against the ValidateEmailAddress operation with a lower timeout value. This should get nearly all of them. Continue this until all the emails have data for the SMTP level checks. The more you submit an email, the better the chances are that our background processes will be able to process it. Our system improves with use.

How fast is the service?

This value will tell the service how long to take when trying to communicate with the SMTP server. If a lower value is given then the service may not be able to successfully communicate with a slower mail server. If possible we recommend a timeout value of 30 seconds. Not all mail servers will take this long to respond but some will and a higher timeout value will ultimately produce the best results.

My email address fails EV3's SMTP level checks, but I know it is a valid email address.

Your mail server may be down, or extremely slow. If we cannot get a response from the server there is nothing we can do but assume it is not valid. You can also send us the email address at and we can double check that the service is working properly.

Where do you get your information?

We get our data from a variety of public and proprietary sources. We also do real-time checks, as well as have background processes that are constantly getting new data.

I'm not technical, but I have a list of email addresses I want to validate. Can you run my list for me?

Yes! We run EV3 batches for users quite often, and would be happy to run your list once we discuss your needs. We offer a free trial batch for up to a hundred emails. Please contact for details.

The sample code is giving strange errors or is crashing!

Most likely, the sample code cannot connect to Service Objects. Many environments will not allow you to connect out on port 80, or will clip out XML data from these requests/responses. The easiest way to check for this is to open a browser on the machine running the sample code. In your browser, navigate to: Then test one of the operations with your trial key. If you get a browser error, or get no data back, then the sample code isn't able to connect, either. Contact your systems administrator to resolve why you are not able to connect to Service Objects.

Why are email addresses Scores for Hotmail, Yahoo, and other domains commonly marked as a one, "Probably Good", even though I know they are valid?

Email providers like Hotmail and Yahoo have catch-all domains. They will accept requests for any email address, even for addresses that do not exist. It is difficult to be certain on whether an email address with a catch-all domain is truly valid or not. This uncertainty is generally the reason why an email address will be marked as either one (Probably Good) or three (Probably Bad).


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  2. Tackling False Positives in Email Validation

  3. Email Validation: To Correct or Not to Correct?

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  5. Best Practices for DOTS Email Validation

  6. How to Use DOTS Email Validation 3

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