Email intelligence
Disposable email detection that respects real users
Every fake signup, repeat free trial and self-referral starts the same way: with an inbox that will not exist tomorrow. Guarda checks the domain of an email address against a continuously updated disposable-provider database and returns a verdict in the same request flow as your IP intelligence — so fraud is stopped at the form, not cleaned up after.
What we flag
Throwaway inbox providers
Services built to hand out an inbox that self-destructs after ten minutes. The classic fake-signup vehicle: receive one confirmation link, abandon the address forever.
Temp-mail APIs and rotating domains
Programmable inbox services that mint fresh domains constantly to dodge blocklists. We track the operators rather than individual domains, so new rotations are caught as they appear.
Burner and forwarding aliases
Addresses that exist only to forward elsewhere or to be discarded. Legitimate for personal privacy in some contexts, but a strong fraud signal on trials, referrals and promo codes.
Allowlist first
Detection is only useful if real users pass. Hundreds of verified legitimate providers — Gmail, Outlook, Yahoo regional variants, ISPs, universities — are pinned to an allowlist that always wins over the blocklist, so a sloppy feed can never lock out real customers.
One call, one verdict
GET /api/public/v2/email/<address> — each check counts as one query against your daily quota. Only the domain is matched; we never store full email addresses.
curl "https://guarda.net/api/public/v2/email/test@mailinator.com?key=YOUR_API_KEY"
{
"status": "ok",
"email": "test@mailinator.com",
"domain": "mailinator.com",
"disposable": true,
"checked_at": "2026-01-01T00:00:00.000Z"
}| disposable | true when the domain belongs to a known disposable provider. |
|---|---|
| domain | The matched domain. Only domains are matched — full addresses are never stored. |
| checked_at | When the verdict was computed. |
Where it earns its keep
Signup fraud
Block throwaway addresses at registration before a fake account ever reaches your database. Pair with Guarda's IP check to catch VPN and proxy signups in the same request flow.
Free trial abuse
One real customer, thirty trials. Disposable addresses are the fuel for repeat-trial farming; flagging them at the form is the cheapest fix.
Referral and promo farming
Referral bonuses and discount codes attract self-referrals through burner inboxes. Rejecting disposable domains at claim time keeps campaigns honest.
List hygiene
Disposable addresses hard-bounce within hours and drag down sender reputation. Screening at capture keeps them out of your mailing list entirely.
Freshness and false positives
Disposable providers rotate domains constantly, so the database is synced daily from multiple trusted open-source feeds rather than shipped as a static file. Provenance is tracked per domain, which lets us audit where every verdict came from.
Blocklists alone produce false positives — several public feeds mix legitimate freemail providers into their data. Guarda runs a curated allowlist of verified providers that always overrides the blocklist, cross-referenced against independent traffic rankings. A domain on the allowlist can never return a disposable verdict, no matter what a feed claims.
Need an exception of your own? Manual allow and block entries from the dashboard survive every sync.
Free to try, paid at scale
Single checks are free for everyone in the disposable email checker. Dashboard batch checks and API access are included with every paid plan, sharing the same daily quota as your IP lookups — one key, two detections.