What are the best tools for checking if an email address is valid?

There’s no foolproof method to ensure an email is valid without actually sending one and getting a response. However, you can use DNS checks and block lists to filter out some clearly invalid addresses. Some services may offer API checks, but they often face limitations or changes in how those services operate.

If you're looking for something with real-time verification, check out Mailgun's email validation API—it’s designed for this purpose. For bulk validation, Clearout and EmailListVerify are also highly recommended as they minimize false positives when identifying invalid addresses.

Using a tool like Zerobounce is also a smart choice; they claim about 99.6% accuracy. Have heard good things about them for bulk checks, plus they offer different validation methods to suit various needs.

I've had good experiences with NeverBounce and ZeroBounce for smaller batches. Recently, I've also tried Snovio's verifier, and it has caught some bad emails that the others missed. If you're doing bulk checks, you might want to compare the results from different services to see which works best for you.