Guide
Why websites block temporary email addresses
Websites block temporary email because an address nobody owns makes it cheap to claim free trials again and again, open spam accounts, or sign up without ever being reachable. Most do it with a few quick checks on the address itself, and some look at how you behave as well. Knowing which check stopped you tells you what to try next, and when to stop trying.
By Bathan DevUpdated 4 min read
Why sites block temporary email at all
Sites block temporary email because an address nobody owns makes abuse cheap. A free trial limited to one per email can be claimed over and over. A referral bonus can be paid out to accounts that belong to no one. A forum can fill with spam from accounts made in seconds and thrown away. Refusing disposable addresses raises the cost of all of that.
There is a plainer reason too. A site that asks for your email wants to reach you later, for receipts, security alerts or marketing. An address that stops working next week is no use to it, so some sites refuse one simply because it does not serve them, even when nobody is abusing anything.
None of this is personal. The check runs on every sign-up, and it is usually blunt.
How sites detect a disposable email address
Most sites check the address itself, and some also look at how you arrived at the form. The commonest check is a block list: a collection of domains known to belong to temporary email services. If the part after the @ is on the list, the form refuses it before any mail is sent, which is why addresses on a temp mail service’s own domain are turned away so often.
A step further is a mail server check. The site looks up which servers receive mail for the domain, its MX records, and refuses a domain with none, or one whose mail goes to servers tied to disposable services. Some sites also have rules for the part before the @: refusing a +, or stripping dots and tags before comparing, so that u.s.er@gmail.com and user+x7k@gmail.com are both treated as user@gmail.com.
Behaviour checks look past the address altogether. Many sign-ups from one network in a short time, a form filled in faster than a person types, or a pattern the site has seen from spam accounts before can each lead to a refusal, a CAPTCHA, or an account that is quietly limited later.
Try it nowGet a temporary Gmail address in one click. No sign-up.
Get temp mailWhy a gmail.com address usually gets through
A gmail.com address usually gets through because a site cannot block the domain without turning away every Gmail user. Its mail is also handled by Google’s own servers, so neither a block list nor a mail server check has anything to catch. The addresses here are real gmail.com and googlemail.com addresses on shared accounts, made with Gmail’s dot and +plus behaviour, which is why a temporary Gmail address is accepted where a throwaway domain is not.
It does not get through everywhere. A form that refuses a + will refuse the +plus style. A site that strips dots and tags sees the mailbox underneath, and because the accounts are shared, someone else may already have signed up there with a variation of the same one. A few sites block shared-inbox services whatever the domain.
The custom domain style is a different case. It is not Google’s domain, so whether it is accepted depends on whether that domain is on the lists a site uses.
What to try when temp mail is not accepted
When an address is refused, change one thing at a time: the style, then the pool, then the address. If the form rejected a +, switch the style to Gmail dots, which read like an ordinary name; the Gmail dot trick explains why they still reach the same inbox. If dots fail too, try Googlemail, an older spelling of the same service.
If the style is not the problem, choose the private pool, which uses privately managed accounts instead of the public shared ones. Or simply generate a fresh temporary Gmail address: a new address may sit on an account the site has not seen before.
If the address was accepted but no mail came, the problem is further along. A sender may refuse to send to an address it distrusts, and mail that is never sent never arrives. Give it a minute, press Refresh, then try a new address in a different style.
When a refusal means you should use your real address
If a site refuses every temporary address you try, take it as a sign that it expects to reach you, and ask whether that is fair. If the site handles money, identity or anything official, the refusal is doing you a favour: a temporary address should never go there anyway.
The same goes for an account you expect to keep. Getting past the check is only the first step, because every reset link and receipt afterwards goes to the address you gave. If you would need any of that, use your real email instead.
And respect the reason behind the rule. If a site limits free trials to one per person, a new address does not change what you agreed to. Nothing gets through everywhere, and a site that has decided to check hard will usually win.
Questions
Why was my address accepted but no code arrived?
The sender may have refused to send to it or filtered it after sign-up, and mail that is never sent never arrives. Press Refresh after a minute, then try a new address in the dots style.
Does the custom domain style get blocked more often?
It can. A custom domain is not Google’s, so whether it is accepted depends on whether that domain is on the lists a site checks. A gmail.com address cannot be blocked that way without blocking Gmail.
What if every style and pool is refused?
Then the site is checking more than the address, or blocks shared-inbox services outright. If you still want the account, use your real email or a second address of your own.