One wrong vendor is enough to spoil your long term plans, I have learned it the hard way. Now I spend extra time in judging the quality of services of any vendor rather than believing them blindly. I did the same before finalising my deal with Clearout, the best email verification service.
You may go through my research on Clearout which included the following
Level of Accuracy - I used the 100 free credits on sign up to test the accuracy for both bulk and real-time verification. Compared it with the results from other tools to find that Clearout was more efficient in Yahoo Account Verification, Catch-All Account Verification, Syntax Verification, Disposable Email Verification, Role-based Account Verification, Domain Verification and MX Validation.
Turnaround time - Together with accuracy, TAT plays important role in the email verification. There are bulks of data to be verified on a recurring basis. I was able to verify a million email addresses in less than 120 minutes. The tool I used earlier took more than half of my day.
Pricing - I actually asked my employees to make up a price comparison table for the top 15 email verification tools. The pricing difference goes more than 50%. Clearout's pricing seems reasonable as it has both one-time payment and monthly/yearly subscription plans.
Support System - Do test the support system before finalising any product. The Clearout supporting team is available 24*7 to patiently listen to your queries and resolve them at the earliest. I admire it a lot.
Abiding the law - We as a user usually ignore the privacy policies and later suffer. Clearout complies 100% with EU's GDPR and its data-saving policies are totally transparent.
Integrations - Do check whether the ESP/CRM you use integrates with the email verifier or not. Earlier I was using Mailchimp which seamlessly integrates with Clearout. But now as Clearout has launched COFS (Clearout for Google Sheets) I save and verify my data directly on Google sheets.
Hope this was helpful, if not I will suggest you have a look at the comparison among the top email verification tools.
Searching Zerobounce, it will give you the best possible email validation service. Great tools, easy to use website and awesome customer support service.
You can try DataValiation.com - competitive prices, fast turnaround times and great accuracy! We've been on the market since 2007 and have a great reputation among email marketing professionals.
Give us a try - www.datavalidation.com