Coming soon: all new

Faster, easier, more powerful. Many bugs and usability issues are fixed.
Try it here and send us some feedback. (yes we fixed the ContactUs form)

Available Tests

(scroll down for an informal guide to everything)
  • Individual Subscription


  • Professional Subscription


  • Corporate Subscription


    • Multiple: User Logins
    • Automatic: Schedule recurring tests
    • Monitor: Integrate our tests with your systems
    • WalkThru: See how easy Automatic Monitoring is to setup

Subscription info...

Millions of Tests performs over six million tests every year. Our test count has gone up every month since we started in January 2010.


Have regulatory and compliance email requirements? We have simple, easy, and inexpensive solutions! More...


Secure email is not "set it and forget it", and sooner or later something will go wrong. Make sure none of your emails ever show up on the cover of a news tabloid!

  • Monitoring

    • You can build custom email security monitoring with a Corporate Subscription to CheckTLS, or we can do your monitoring for you. Monitor your own infrastructure, your trading partners, or both. More...
  • Whitelist

    • Your firewalls and/or intrusion detection systems may view a series of tests as a threat and block them. Prevent this by whitelisting the IP addresses: (i.e. 112-115).

Informal Guide To Our Tests

So you have an email address and you want to know if it can receive a secure email. Use our Basic Receiver Test.

If it shows that something is wrong, use the Detail output level on that same test to expose the problem.

Now you want to know if you can send a secure email. Use our Basic Sender Test.

But what about your home email account, can it send secure email? Remember it uses special settings from your Internet Provider to receive email from your PC. Use our Custom Receiver Test. It lets you enter settings like SMTP gateway, port, and your user-id and password.

Now your tablet PC won't send email. Should be easy to fix if you could just see what it's sending and receiving. Use our Watch A Connection Test. It can sit between the two sides and let you "listen in".

At work, company policy says you must use TLS with certain trading partners. If TLS fails on either end, no email should go through. Use our AssureTLS Receiver Test and AssureTLS Sender Test.

Informal Guide (Continued)

Your company sends to lots of email addresses, and you're asked to check them all. And you'd like to keep testing them every now and then, but only get notified if something's changed. Use our Batch Test.

What you'd really like is to alert your on-call people when Batch Test finds a problem. Use our MonitorTLS Web Service. It integrates with most monitoring and notification systems.

So you need an unsigned SSL cert for some testing. Make one right here.

Want to know what's inside an encoded cert? Show it right here.

Need to re-key your cert without paying for a new one? You'll need to know exactly what is in the certificate signing request (CSR) you used years ago. Show what's inside a CSR right here.

Your Exchange Server won't sync and you want to telnet to the IMAP port, but you forget the IMAP syntax and it's TLS encrypted besides. Use our IP Services Test. It will test POP and IMAP and HTTP and other services as well!