Disposable email domains on your list
Disposable domains exist to receive one message and vanish: mailinator.com, guerrillamail.com, 10minutemail.com, temp-mail.org, sharklasers.com and hundreds more, including rotating subdomains of the same service.
They accept mail, so they never bounce. They also never convert, and the inboxes are public in some cases — anyone can read what you sent.
Why they are worse than they look
Three costs. They inflate list size and depress every rate you calculate from it. They waste send volume on people who will never buy. And some services publish received mail publicly, so a poorly judged campaign becomes searchable.
For a security-sensitive product, a disposable address is also a signal: the signup was a test, not a customer.
Detection is a domain problem
You cannot detect disposables from the local part — x7k2@mailinator.com looks like any address. Match the domain against a maintained list, and account for subdomains: anything.mailinator.com is the same service. Lists go stale, which is why a static file needs occasional refreshing rather than being written once.
Where they legitimately belong
Some teams keep disposables out of the marketing audience but allow them past signup so people can trial a product without handing over a real address. That is a product decision — just make sure the disposable segment never enters a paid-send audience.
The related trap: catch-all domains
A domain configured to accept all mail will accept anything@thatdomain.com. That is not a disposable service, but it behaves similarly for your purposes: you cannot tell a real signup from a fabricated one without sending, and sending is what you were trying to avoid.
Check your own list in about 30 seconds. Paste or drop a CSV — duplicates, typos, role addresses and dead domains, all handled in your browser. Free for the first 100 addresses, $19 once for unlimited.
Open the toolCommon questions
Should I block signups from disposable domains?
If your product depends on reaching the person later — password resets, invoices — yes. Blocking at signup is cheaper than discovering it at renewal time.
How often do disposable lists go stale?
New domains appear constantly, so any static list drifts within months. Re-check the domains you see most often in your own signups rather than trusting a list to be complete.
Last updated 2026-10-23.