How to check fake email addresses

Fake emails are annoying. They waste your time, eat up resources, and mess with your data.

Whether you’re running a service, offering a free trial, or just trying to keep your user base clean; spotting fake email addresses early matters.

You don’t need a huge team or fancy software to do it, either. With the right tools you can catch most of them before they cause problems.

This post walks through the basics, like what fake emails are, how to spot them, and what you can do to stop them dead in their tracks.

What counts as a fake email address?

A fake email address is pretty much what it sounds like - an email that isn’t real or isn’t meant to stick around.

But it’s not always as simple as just “made up”. There are a few types.

You’ve got disposable emails. These are real, but only for a few minutes. Someone grabs one from a throwaway email site, uses it to sign up for something, and vanishes. No trail. No replies.

Then there are flat-out nonsense ones - like [email protected] - which obviously aren’t going anywhere. These are often used by bots or people who just don’t want to give you their actual contact.

And then there are “lookalike” emails. Tricky ones. These use sneaky domain names that look valid but aren’t. Stuff like @gma1l.com instead of @gmail.com. Easy to miss, especially if you’re scanning fast.

“fake” can mean short-lived, made up, or just shady. And spotting them early can save you a load of hassle.

Why do people use fake emails anyway?

People use fake emails to dodge spam, skip signups, or grab a free trial without getting nagged later.

Some just want to peek behind the curtain without actually committing to anything, while others are up to worse: Bots spinning up fake accounts to abuse services, test stolen cards, or flood your platform with junk.

And that’s where things start costing you time, money, and sanity.

The signs of a dodgy email (and when to be suspicious)

1. Weird domains If the domain ends in .ru, .xyz, .click, or something odd you’ve never seen before… maybe don’t trust it.

2. Random letters [email protected] isn’t someone’s actual name. That’s someone in a rush trying to get past your signup form.

3. One-and-done addresses If the same domain keeps popping up, but never repeats the local part (the bit before the @), you’re probably looking at disposable mail.

4. No MX records If the domain doesn’t have mail servers (MX records), it can’t actually receive email. So why sign up with it?

5. Recent domain Brand new domain? No website? Never seen before? Yep - be suspicious.

6. Zero engagement They signed up, never confirmed, never logged in again. Ghosted. Probably never intended to hang around.

Spot one of these? Mild concern. Spot a few at once? Time to block it.

Disposable vs. made-up: There’s a difference

Not all fake emails are created equal though. Disposable emails for example are real. They actually work - for a short time. Services like TempMail or EmailOnDeck let users spin one up, use it for 10 minutes, then forget it.

They can receive emails. They will pass basic validation checks. That’s what makes them annoying. Made up emails, on the other hand, don’t even try. Stuff like [email protected] or [email protected]. They usually point to domains that don’t exist or can’t handle email at all.

So where’s the problem?

Well, disposables are the sneaky ones. They let someone look legit, bypass your form, grab your trial, and then vanish. Made up ones are easier to catch. But they still clog up your system if you’re not filtering properly.

The trick is knowing which type you’re dealing with. That’s where tools like Temp Mail Detector work great.

How Temp Mail Detector spots them (and doesn’t miss much)

Temp Mail Detector keeps things simple. You give it a domain, and it tells you if that domain is known for temp emails. That’s it. No full email addresses. Just the domain. Like mailinator.com or sharklasers.com.

This keeps it privacy friendly and doesn’t share any personal data,

The API checks against a massive list of known disposable email domains, with new ones getting added every day.

Temp Mail Detector crawls the web, keeps an eye out for new domains, and adds them to the blocklist automatically. It runs in the EU, so everything’s GDPR-friendly and tidy and it’s fast, and you can include it into your signup flow without drama.

One questionable domain in, one qualified answer out.

Not ready to use an API? Then we also have a free two month delayed list of domains available on our GitHub you can use.

What to do after you spot a fake mail

So you’ve caught a fake. Now what?

You’ve got a few choices and it depends how strict you want to be.

1. Block it outright Simplest option. Don’t let the signup happen. Show an error like “Please use a valid email”. You save your resources. They move on.

2. Let it in, but limit stuff Maybe let them poke around, but don’t give them full access. No free trial, no promo codes, no API keys. Keep them in the shallow end and save your AI Credits for actual users.

3. Flag for review Log it somewhere. If you’re seeing lots of fake signups in a short time, something dodgy’s probably going on which needs your attention. Maybe it’s time to use a Captcha?

4. Don’t bother emailing them Skip the welcome email. No point emailing [email protected] - they’re not reading it. And if they don’t get a verification email, they can’t onboard.

5. Improve your flow If fakes keep slipping through, tweak your signup form. Add email verification. Use run your verifications earlier. Maybe rate-limit the signups.

Catching a fake is good. Making sure they stay out is important. That’s where Temp Mail Detector can help you improve your user quality and reduce abusive users.