You're about to hand your entire email list to a vendor. So what actually separates a trustworthy one from a time-waster? Five things, and none of them is the accuracy number on their homepage.

Start with accuracy. A good provider won't just say they're accurate. They'll show you proof, an independent audit, or they'll let you run a sample of your own list through their tool first. And ask the one question that matters: do they actually connect to the mailbox server to check, or do they just read DNS records and a database? The ones that connect catch more.

Second, look at the labels they give back. Run away from any vendor that only says "valid" or "invalid." You need more shades than that. At minimum: valid, risky (the syntax is fine but the domain looks fishy), unknown (no data yet), disposable (a throwaway inbox), and invalid. The risky ones are exactly the addresses you most need flagged, so a tool that hides them is doing you no favors.

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Third, check how open they are about their method. How fresh is their throwaway-domain list? Do they explain which checks they run, and in what order? Is there a public status page you can actually look at? A vendor that won't tell you how it works is a red flag, plain and simple.

Fourth, make sure the plumbing is solid, with a published uptime guarantee. For a big batch job, raw speed matters less than accuracy. But if you're checking addresses live as people sign up on your form, a slow tool will drag down that whole experience. That uptime promise has its own name, an SLA, and it's worth its own video.

And fifth, the one that settles it: once you've got two or three candidates, run a sample of your own list through all of them and compare. A provider that catches fifteen percent more real problems than the next one might well justify paying more. You only find that out by testing, not by reading a badge.

So: proof over promises, granular labels, an open method, real uptime, and your own sample test as the tiebreaker. Hold every vendor to that, including the one you already use.

Next up: what a validation SLA actually guarantees, and why the difference between ninety-nine and ninety-nine point nine percent is bigger than it looks. Subscribe, and drop your question below.

What should you look for in an email validation provider? Five concrete checks, and the accuracy number on the homepage isn't one of them. We cover proof over promises (independent audits, or a sample test on your own list), why the labels a vendor returns tell you how deep it actually checked, why transparency and a public status page are green flags, why uptime matters most at the live signup form, and why running your own sample through two or three finalists is the real tiebreaker.

Next: What is a validation SLA? → [link 005.013.002]

Full written guide → reviewmyemails.com/emailalmanac

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