Zerobounce is the greatest tool when it comes to email validation. Catch-all emails, abuse, spamtraps, deliverability tools (Inbox Tester, Email server tes, Blackmonitor), API, bulk file, single email validator,easy and friendly to use user dashboard, almost everything you can think of? It has it. Accuracy hits the roof. It also has a great documentation and 24/7 support team ready to give the best service ever.
I would certainly recommend ZeroBounce.net. It's the most accurate and can help remove abuse/complainers as well as spam traps. They also give you the highest level of detail on status and sub-status of the query so that you can make the best decision possible.
Also, the live chat team is great and actually real people.
Based on my personal experience I will recommend Clearout as the best email verification service available today. Features that keeps it ahead of others:
20+ validation checks on each email address to provide 98%+ accuracy which is considered to be the highest.
Quick integration with all top ESPs and CRMs. Even if you get stuck somewhere the extraordinary support system is there to guide you step-by-step.
The API delivers the results in the fastest turnaround time. Infact, as per the recent audit of List Cleaning Advice, Clearout was ranked #1 for the same.
The clear and detailed segregation of valid, invalids, disposables, honeypots makes our job easier.
The Guaranteed Deliverables keeps bounce rates to the minimum.
And now Clearout is available as a Google-Sheet Add-on so I don't use a paid CRM anymore. I save my data on free Google sheets, use CLearout to verify the data directly on google sheets and have been successful in saving a lot of my expenses.
I'm using ZeroBounce.net for 2 years today! The reason why I'm choosing them is due to their features: the A.I. Email Scoring helps me a lot with my Catch-Alls. Also, I've seen they have new deliverability tools that help us to have better control of our campaigns after validation of the database, I just tested it and I can see where my emails will end up if in the Inbox of my customers or in their Spam folders.