Real-Time Email Verification: The Sweet Spot

Real-time verification is probably the most effective approach to collecting clean email addresses online. By informing the user -in real-time- about the validity of the email address typed, you keep the number of conversions high, while guaranteeing that only valid email addresses are submitted to your list.

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But that's easier said than done. Validating email addresses on a web page poses some challenges. On one hand, validating the address format can be tricky, since not all email providers follow the same standards. A JavaScript regular expression simply won’t cut it.

On the other hand, validating the address format doesn’t guarantee that the address corresponds to a real inbox. Only SMTP verification can guarantee this.

 

 

The Paradox of SMTP verification

SMTP verification means contacting an email server to send an email to a particular address but exiting before the sending is confirmed. The objective is to find out if the server is accepting that particular email address or not.

Many providers offer SMTP verification, which is extremely useful for validating mailing-lists in bulk, but has serious limitations when it comes to real-time verification:

  • Time: Depending on the SMTP server, an SMTP verification can take a few seconds. That’s not what I call ‘real-time’.

  • Reliability: SMTP servers might be busy or simply down. In which case a valid email address might not be accepted. How frustrating is that?

  • Price: The average price for SMTP verifications is around $5 per 1000 verifications. Even if you can afford it, would you be comfortable putting the key to such a service on a public webpage?

While SMTP verification remains the ultimate email verification tool, it is nevertheless unfit for real-time verification. Instead of hurting my conversion rate with a slow verification process, I would rather accept a few unvalid email addresses that I can clean up later, and keep my page nimble and thrifty.

 

The Sweet Spot

The sweet spot of real-time email verification is somewhere between regex verification and SMTP verification. A service that verifies most aspects of an email address, without the complications of contacting the SMTP server.

A real-time email verification service must:

  • Perform advanced format verifications, considering specificities of common email providers.
  • Make sure the domain has valid MX records.
  • Suggest corrections to common typos.
  • Be fast enough to give an impression of real-time.
  • Be affordable and secure enough to be used on a public page.

Verimail is our attempt at creating such a service. It will do advanced email format verification, check the domain’s MX records and suggest typo corrections in about 300ms. It will also detect and authorize requests coming from your domain, so you don’t need to put your API key on a public web page.

For the price, don’t ask! It has a free quota of 1000 verifications/month, and paid plans cost 10 times less than the average SMTP verification.

See verimail in action here