Email domain check
Is mailnull.com a disposable email domain?
Yes: mailnull.com is a temporary inbox service. Here is what that means for your signup form, with mail-server data checked in Oct 2026.
Yes. mailnull.com is a temporary inbox service: anyone can read or create an inbox there in seconds, so a signup from it is almost never a customer.
mailnull.com at a glance
| Check | Result |
|---|---|
| Type | Disposable |
| On the disposable list | Yes |
| MX records | mx.mailgw.com |
| Mail operator | Self-hosted throwaway service |
| Checked | Oct 2026 |
Why signups from mailnull.com cost you money
People reach for mailnull.com when a form asks for an email they do not want to give: to grab a free trial, a discount code or a download. The account looks real in your database, but the welcome email, onboarding sequence and receipt all go to an inbox nobody reads again.
The damage is quiet: inflated signup numbers, trial-to-paid rates that look worse than they are, bounces that hurt your sender reputation, and in the worst case one person farming endless trials with a fresh mailnull.com address each time.
How to block mailnull.com on your signup form
The quick fix is a domain check before the account is created. Our free list of disposable email domains includes mailnull.com and is public domain (CC0):
const res = await fetch('https://usevetto.com/disposable-domains.json');
const throwaway = new Set(await res.json());
function isThrowaway(email) {
const domain = email.split('@').pop().toLowerCase();
return throwaway.has(domain); // true for 'mailnull.com'
}A static list goes stale within weeks, because new throwaway domains appear daily. Vetto keeps the list current, also checks the domain's mail servers live, and shows the visitor a friendly message instead of a dead end.
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Frequently asked questions
Is mailnull.com a temporary email service?
Yes. mailnull.com is on Vetto's list of disposable email domains: anyone can receive mail there without an account, and the inbox is usually public or deleted after a short time. Treat signups from it as throwaway.
Should I block mailnull.com on my signup form?
For a free trial or a freemium product, yes: people use mailnull.com to grab a trial without giving a reachable address, so the account never activates or pays. Show a friendly message asking for a real address instead of a silent error.
Can mailnull.com receive email?
Yes, it publishes MX records (mx.mailgw.com), which is exactly why it works as a throwaway: the code arrives, the person copies it and never comes back.
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