Block disposable email addresses where they cost you money
Your free trials are being farmed, or one person keeps claiming a first-order discount with a new address each time. Both are real costs, and a disposable check at the form is the cheapest first fix.
Start by pricing the problem. A repeated free trial that burns compute is worth blocking. A burner address on a newsletter signup costs you one row, and a tag handles it better than a block. The disposable domain list shows how many domains it holds and when it last changed.
The order the work happens in
Put a price on the abuse
Count what one fake account costs: trial compute, a coupon, a sales call booked for nobody. That number tells you whether to block, tag or ignore.
Block at the form, not in the database
Refusing at signup gives the person a chance to use another address. Finding the row later means you've already sent them mail and stored a record nobody will read.
Read the flag on every check
ZapBounce returns a disposable flag beside the result on every check, from the same list the free checker uses. You get it with the verdict you already pay for.
Add a second control where money is at stake
A confirmation click, a card or a phone number defeats throwaway addresses by design. Use the flag to decide which signups need that extra step.
Review your block log once a month
A blocked domain that turns out to be a privacy forwarding service is a customer you turned away. Reading the log is how you spot it and unblock the domain.
What each result means here
The same four results and their flags, read against this job. A catch-all worth keeping in one situation is one to exclude in another.
| Result | What to do with it |
|---|---|
| Valid | A disposable address usually is valid: the mailbox works today and is gone next week. Act on the flag, not the result. |
| Invalid | Remove it, like any dead address. |
| Catch-all | Some throwaway services run catch-all domains, so both labels can appear on one row. |
| Unknown | Unrelated to the disposable question. The flag still comes back, and the unknown is free. |
| Role flag | Rare on throwaway domains, and it tells you little when it appears. |
| Disposable flag | Block at signup where abuse costs money. Otherwise keep the row and tag it. |
How you know it is finished
Signups from known throwaway domains are refused at the form with a message that lets the person try again, and the abuse you were worried about has actually fallen rather than moved somewhere harder to see.
Worth planning for
The disposable flag is a list lookup, so it rides along with every check at no extra cost: $5 buys 1,000 checks, and credits never expire. The free disposable email checker runs the same lookup on one domain with no account.
Questions people ask
Should I block disposable email addresses at signup?
Where a throwaway signup costs you money, such as a compute-heavy free trial, yes. For a mailing list, tag the address instead, because a block there turns away real people for little gain.
How does ZapBounce detect disposable emails?
By domain list lookup. ZapBounce merges the open-source disposable-email-domains list with its own additions, refreshes it weekly, and sets the disposable flag on any address whose domain is on it. The lookup is instant and gives the same answer every time.
Are privacy forwarding services disposable?
Usually not. Services people use as a permanent forwarding address behave like real mailboxes and belong to real customers, and blocking them is the most common expensive mistake here.
Is a disposable email address the same as an invalid one?
No. A disposable address usually works today, so its result is often valid. The disposable flag is a separate true-or-false field, which keeps the verdict and the throwaway signal apart.
Try it on the file in front of you
100 free checks a month, no card. Addresses we could not get an answer on come back labeled as unknown, and those are not billed.