Disposable Email Detection — 50,000+ Throwaway Domains Tracked

Why disposable inboxes matter

A disposable (or 'throwaway', 'temp') email is an address that exists for minutes and then vanishes. Users sign up for one to grab a free trial or claim a discount and never see another message. From a marketer's perspective every disposable address on your list is paying you in zero — they cost a credit to verify, a send to deliver, and never convert.

Worse: many ESPs treat outreach to known disposable domains as a soft spam signal. Even a small percentage on your list pulls your sender score down.

How KillBounce tracks disposables

A weekly-refreshed blocklist combining curated public feeds with internal additions, cached for sub-millisecond lookup:

1. 01

   Refreshed weekly

   The blocklist is refreshed weekly from multiple sources we curate, then merged with internal additions tracked against fresh disposable providers. New providers usually land on the list within days of going live, well before mainstream blocklists pick them up.

2. 02

   In-memory lookup

   Domains are normalised and stored in memory so a check is sub-millisecond against 50,000+ entries. Verifications never block on a cold database lookup, and the disposable check stays well inside the typical under 900 ms envelope.

3. 03

   Match on full domain + suffix

   Both exact-match (foo@mailinator.com) and known-suffix patterns (foo@subdomain.mailinator.com) are caught. Many providers spin up unlimited subdomains specifically to evade naive blocklists — the suffix match is what closes that gap.

4. 04

   Flag on every verification

   Single, bulk, and API responses all return an is_disposable boolean. The disposable detector runs independently of catch-all detection — an address can be one, both, or neither.

Disposable providers we catch

The list is too long to enumerate (50,000+ entries) but covers all the major providers plus the long tail. The big names:

• Mailinator (and all *.mailinator.com subdomains)
• 10minutemail.com / 10minutemail.net / 10minutemail.org
• Guerrilla Mail (guerrillamail.com + all aliases)
• Yopmail (yopmail.com + 20+ aliased domains)
• Temp-Mail.org and clones
• Maildrop.cc, DropMail.me, MintEmail
• Throwaway.email, Tempr.email, Trashmail
• Plus 49,000+ smaller / newer entrants

New disposable services launch monthly — sometimes weekly during free-trial-abuse waves. The community feed typically picks up new providers within 7–14 days of their public launch. KillBounce's weekly refresh means our coverage stays current without you doing anything.

Illustrative impact on signup quality

Filtering disposables at signup tends to improve every downstream metric — but the magnitude varies a lot by industry, baseline list hygiene, and signup motion. The table below is illustrative of the direction we hear from operators who turned it on, not a guarantee or a measured study:

The mechanism is the load-bearing part: disposable signups are fake by definition — they exist to claim something (a free trial, a discount code, a download) and then disappear. Filtering them improves the metrics that depend on you actually reaching real people. Your numbers will look different from ours; measure your own baseline before deciding what to optimise.

Where to filter disposables

There are three places to block disposables, in increasing order of effectiveness:

1. 01

   At signup (highest leverage)

   Integrate the KillBounce API into your signup form. When a user submits, validate the email server-side before creating the account. Disposables are blocked at the door — never enter your database, never count toward MAU metrics, never get a welcome email. This is the only place where filtering scales — every other approach is cleanup after the fact.

2. 02

   On the email list before send

   Bulk-verify your list with KillBounce before each campaign. Disposable addresses get flagged so you can suppress them from the send. Less ideal than blocking at signup, but catches contacts that slipped through.

3. 03

   On your CRM during periodic cleanups

   Quarterly bulk verifications catch disposables that entered via partner signups, imported lists, or signup form gaps. Filter them out as part of regular list hygiene.