How far should I take email address validation when the cost of bad emails is high?

Question

When it's more important to prevent typos than to cover 100% of all possible email addresses, what syntactic email validations do you do?

Imagine this:

You're with the local gas & electric company. 10% of new installations are cancelled because the customer is not home and it costs your company $50 a pop. You start taking email addresses with the new install orders so that you can send reminder emails the day before the appointment. You bring that number to 0% when you have a deliverable email. The only problem is that 15% of all the emails you take bounce back because of some typo. Email addresses are recorded by call center agents who talk to the customer over the phone.

In this case, it's important to collect a valid email address. It's also not all that bad if someone cannot successfully use an email address like:

"Big Momma D.'s #1 CA$H Maker, BOY!!!"@naturalhistory.museum

My guess is that Big Momma D. can't use this email anywhere and either doesn't really use email, or has more conventional email address to use.

This is related to this more general question: How far should I take e-mail address validation?

Let's throw a few more assumptions on here:

1. This is in the US, so it's unlike people will have email addresses like 漢字@gmail.com (good luck communicating that to a call center agent in Austin, Texas)
2. Validation emails are not suitable, since the customer is only in contact with us by phone

Answer 1

You should simply test sending an email to the given address. If the email is valid, it should reach the user's inbox and the user can click on a link to validate the email and continue registration. If the user did not receive the registration email, then they would notice that they typed something wrong. This procedure is pretty much standard nowadays.

Answer 2

First of all, I'd run it through the most basic of regexs for validity. You can find several options, all with their own problems and features at: http://www.regular-expressions.info/email.html. (There's an ugly one down the page that implements RFC 822)

However, what you have here is a business problem, not a computing problem. The solution is simple: "Your appointment for installation is XXXXXX. Should you miss this appointment without contacting us, you will be billed $50.00, and will have to reschedule."

Answer 3

Nothing is 100%. One day the email server is up. The next it is down. Person used their cable company email and when they moved, no more email. How can you catch [email protected] when it should be jan? Oh, the customer service person would catch this since she's speaking to a female and assumes it's jan instead. Only problem is this is the husband's email; he's the one who's going to be at the house.

You should consider a text message.

Or have phone call reminders go out the day before. And then the service tech calls when they are leaving for the call.

Trust me. I just moved and had every service and delivery you can think of: furniture, cable, alarm system, water softener. They all call ahead.

And that 15% failure is attributed to bad email address and not a failure to be home?

Answer 4

One possible solution: Have them send you an email from their regular email address instead. Give them an email address that's as easy as possible to type. You can reserve a domain just for this. If your company is "MyCorp", you can register "MyCorpEmail.com". Tell them their appointment code is '243' and have them email '[email protected]" (You can vary the domain, the appointment code can be a word, you get the idea.)

Then, when you get the email, you will have captured their email address with no chance of a typo. Just carefully select the email code on your side to make it as easy to type and spell as possible. You can even ask them to send them the email while you're on the phone, if possible.

Answer 5

You may send confirmation email as mentioned above. It's standard practice now, it even have special term for that process - two opt in. But in common you may validate user data BEFORE sending email. 1. You may check is there existing domain used. Is there MX records present on it? 2. You may integrate with some external service like mailcheck.co, that will check email delivering, but also enrich customer data with some additional info, like surname or social profile.

Those checks could improve yours bounce rate, and could be launched on existing email lists to validate them. But anyway - 2 opt in is necessary, those methods can't substitute it.

Answer 6

I've done something similar. I suggest you send them an appointment reminder email the day the day before the appointment (or some other timeframe), with the email coming from a dedicated email account. Have a job that scans that emails' inbox every 15 minutes or so, looking for the returned undeliverable message. Given your email setup, you should be able to compose the outgoing email with a recognizable ID or token, or if that's not possible, you could embed a GUID in the email body itself and check for that. When an undeliverable message comes back, the original message can usually be located and parsed. For emails that come back as undeliverable, locate the customer record in question if possible, then send an item into some kind of high priority queue for an extra human-based phone call to the person prior to the delivery.