Stop fake signups at the source
Block disposable, temporary and undeliverable addresses in real time at the point of registration — before the account exists. Test any domain below. 5 free checks per day — no signup required.
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No email sent to the recipient. Reference list of 8,213 known disposable domains.
What a throwaway address costs you at registration
The damage is not the signup itself — it is everything downstream of it.
Trial and free-tier abuse
A throwaway inbox takes seconds to create, so one person can open account after account. Blocking disposable addresses at registration removes the cheapest way to farm free trials and promotional credit.
Junk in the product database
Fake signups become permanent rows in your users table, your CRM and your analytics. Activation, retention and conversion rates are all measured against a denominator that includes accounts nobody will ever return to.
Sender-reputation damage
Temporary inboxes expire. Welcome emails, password resets and nurture sequences sent to them bounce or land in a mailbox nobody reads, and mailbox providers treat that pattern as a signal to filter the rest of your mail.
Support and fraud load
Accounts you cannot reach by email are accounts you cannot recover, verify or contact. That work lands on support and on whoever reviews suspicious registrations.
Three places to put the check
Same verification, three different moments. Most teams start with the signup form and add the others once the rules are settled.
1. At the signup form
Verify the address as the form is submitted and reject or hold the registration before the account row is written. The disposable flag comes back alongside the deliverability verdict, so you choose which categories are hard blocks.
2. In your backend via API
One authenticated request per address from your registration handler, invite flow or checkout. See the API documentation for endpoints, authentication and response fields.
3. Across your existing users
Export your user table and run it as a bulk check to find the disposable and dead addresses already inside the product, then suppress them from mailings and from your activation numbers.
Beyond disposable detection
The same check also resolves catch-all (accept-all) domains — the addresses most verifiers hand back as "risky" or "unknown" — to a definitive valid or invalid, live and without sending an email to the recipient. Where a signal is genuinely ambiguous the result stays risky rather than a false invalid.
Frequently asked questions
What is a disposable email address?
An address on a domain that hands out temporary, self-expiring inboxes — often public, often with no signup required. They exist so someone can receive one confirmation message and walk away. Alias and relay services are related but different: those forward to a real mailbox and are frequently used by legitimate people.
Should I block every disposable domain at signup?
Block the high-risk, short-lived inbox services outright — there is no ordinary reason to register a paid product with an address that expires in ten minutes. Treat privacy relay and alias services separately: those often belong to real customers, so flagging them for review is usually a better fit than a hard block.
How do I block disposable signups in real time?
Call the VeriMailX API from your registration handler with the submitted address. The response carries a disposable flag alongside the deliverability verdict, so you can reject, soft-block or route the signup for review before the account is created. The check runs against the receiving mail server and no email is sent to the address.
What about the fake accounts already in my database?
Export the addresses and run them as a bulk check. The results mark disposable, invalid, role-based and risky addresses so you can suppress them from mailings, exclude them from your activation metrics and prioritise which accounts to review — without touching your live signup flow.
Will blocking disposable addresses reject real customers?
It can if the list is too aggressive, which is why the disposable flag is reported separately from the deliverability verdict rather than folded into a single yes/no. You decide which categories are hard blocks and which are soft signals for your own risk rules.
Can I test a domain before I wire anything up?
Yes. Use the checker on this page — 5 free checks per day — no signup required. You can also browse the full disposable domain reference to see how a specific domain is classified.
Block disposable signups today
Start with 5 free checks per day in the checker above, or create a free account for API access and bulk checks of your existing users.
Also useful: the disposable domain blocklist and the API documentation.