Disposable Domain Checker
Spot disposable addresses — and the plus-tag trick a blocklist never catches.
Email address
How this lookup works
The domain is checked against a short list of well-known disposable services, and then something more useful happens: the address is reduced to its canonical form. Several providers ignore everything after a plus in the mailbox name, and Gmail additionally ignores dots — so one person can produce dozens of addresses that look entirely different and all reach the same inbox. Comparing canonical forms catches that where a blocklist never will, because the domain is a real one. The list itself is kept short on purpose, since long scraped lists go stale and start rejecting small legitimate mail hosts, which turns away real customers to catch a problem that canonicalisation handles better.
What the results mean
- Disposable
- On the short list of well-known throwaway services.
- Not on the list
- Weak evidence. New domains appear faster than any list is maintained.
- Plus addressing
- The provider ignores everything after a plus, so tags do not create separate mailboxes.
- Reaches the same mailbox as
- The canonical form. This is what catches repeat signups from a real provider.
Common problems and fixes
- A legitimate address was flagged
- Check the domain against the list shown. If it is a small mail host rather than a throwaway service, that is exactly the false positive long lists produce and short ones avoid.
- Someone signed up repeatedly from Gmail
- Compare canonical forms rather than raw addresses. Gmail ignores dots and plus tags, so many different-looking addresses reach one inbox.
- How do I keep the list current?
- You cannot, and neither can anyone. That is the argument for canonicalisation and rate limiting over blocklisting.
Frequently asked questions
Should I block disposable addresses?
Sometimes, and less often than people assume. It stops casual abuse and also blocks privacy-conscious customers who use forwarding services. Rate limiting and canonical comparison usually solve the actual problem with fewer casualties.
Why is the list so short?
Because long lists cause more harm than they prevent. They go stale within weeks and start rejecting small legitimate mail hosts, and a signup form that turns away a real customer costs more than a throwaway account.
What is plus addressing?
Anything after a plus in the mailbox name is ignored by providers that support it, so user+shop@example.com reaches user@example.com. Useful for filtering, and it means tags do not create distinct accounts.
Put this on your own site
Free to embed, no attribution required beyond the source link the frame carries itself. It runs entirely in your visitor's browser, sets no cookies and loads no third-party script.
<iframe src="https://runthetests.com/embed/disposable-email-checker/" width="100%" height="560" style="border:1px solid #e5e5e5;border-radius:8px" title="Disposable Domain Checker" loading="lazy"></iframe>
Preview it at https://runthetests.com/embed/disposable-email-checker/. Embedded pages are marked noindex, so yours stays the canonical copy — not this one.