Thursday, 8 September 2016

Validating Yahoo Email Addresses

Why does the Yahoo domain have to be different?

We often hear from companies who have come to us when they realise they have a hole in their Yahoo email lists, because we accurately validate Yahoo email addresses. Not all email validation companies can do this. We shan't give away our IP here, but we can share a little with you about why some domains are harder to validate than others.

Sliding scales of server suspicion

One of the challenges we face is that different domains are configured to treat email validation companies with sliding scales of suspicion. The irony is that we are helping clean spam, by enabling our customers to communicate with valid email addresses. By scooping out the disposable addresses and the catch-all servers we're helping keep the internet email-litter free.

We use our scale and our "credibility footprint" to stay on easy terms with mail servers. Over the years they have learned to trust us and we've learned how to stay within their rules.

However, in order to check emails we contact servers with queries. Imagine having someone call you up to ask to check your address details. Once is OK. Imagine if they asked you in a way that made you suspicious. You would get fed up and you'd just hang up and not answer the phone.

What are you doing to my server?

Well that's sort of what can happen with email validation. We contact servers in order to check emails. We have to stay within the comfort zones of every server we contact. It's like dealing with different cultures. If we approach in the wrong way - maybe we leave our sunglasses on or show the soles of our feet... servers can freak-out. Listen closely and you can almost hear the code equivalent of; "Whoa who are you?"  "Back up the truck you need to much of my time - are you doing something bad? You act like you're spamming me... That's it, I'm switching you off, come back later. And come back in the right way so I can keep an eye on you...I'm not going to tell you what's bugging me - you go figure it out."

Woman dressed in black points figure suspiciously

Obviously domain servers aren't human, so the voices in our heads are imagined ;) but the humans who set the parameters can change their limits. When we get told to come back later we return a time-out result. Depending on whether you're using as for in-line API services, or verifying a bulk email address list in a static environment, we'll either loop back onto the server that's a bit frazzled, or we'll just tell you we're grey-listed for a while.

Giving our best service is a balancing act of talking properly with the serves and providing a service that is acceptable to our customers. This is really important for retailers using our API as it is part of the customer experience as they travel through your web site. You want to make their journey as smooth as possible, but you also want to make sure they don't leave you with a [email protected] email address and a chargeback further down the line.

Another challenge we face is when domains are split-served, so our request for validation doesn't go the same place. We meet this often, when domains have servers that are configured differently, so we need to understand how to approach them and how to route our queries according to their definition of what is acceptable use.

Our servers are set up world-wide in ways that enable us to provide millions of routing decisions from many requesters via multiple channels and destinations. We like the challenge! It's made all the more enjoyable when you add in that human element - at any time any domain can change any server to accept or deny different levels of validation, based on changes in various parameters that are known only to the IT decision maker. We watch out for new patterns and build in systems to respond to subtle changes.

We shan't tell you the secret of Yahoo domain validation, but hopefully you'll have an understanding now of why not all email validation providers can validate Yahoo email addresses.

For a full non-technical description of our email checking codes read here

For strangely interesting facts about Yahoo read here

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