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COMPARISON

Disposable email detection APIs compared (2026)

Which disposable email API should you use? Eight options compared on price per 1,000 lookups, approach and list size. Prices checked October 2026.

Updated 2026-10-1012 sources

Disclosure: StormDoor makes one of the tools compared here. It is marked in the table.

Prices change. We checked every price on 2026-10-10. Check the vendor's page before you decide.

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Short answer

As of 10 October 2026, the cheapest published per-lookup price for disposable-email detection is UserCheck’s Pro plan at $50 per month for 200,000 lookups ($0.25 per 1,000), falling to $0.143 per 1,000 at 3.5 million [1][2]. Free options exist: two open-source domain lists and two vendor endpoints that answered without a key when we called them. Vendors that also probe mailboxes (Abstract, Kickbox, DeBounce) cost more per lookup. A static list cannot see a domain it has never listed, which is why newer approaches add infrastructure signals.

StormDoor makes one of the tools in this comparison. Its API is not yet open for signups. It is not the cheapest, and we place it by use case.

Key facts#

  • As of 10 October 2026, UserCheck Pro costs $50 per month for 200,000 credits and $500 per month for 3,500,000 credits; one email lookup is one credit [1][2]. #
  • As of 10 October 2026, Abstract API’s email validation starts at $17 per month for 5,000 requests ($3.40 per 1,000) and runs a live SMTP check [3]. #
  • As of 10 October 2026, Kickbox sells verification credits from $10 per 1,000 down to $2,999 per 1,000,000 ($3.00 per 1,000) [5]. #
  • As of 10 October 2026, DeBounce advertises “from $0.00045 per check” ($0.45 per 1,000) and offers a free disposable-domain endpoint [7][8]. #
  • The disposable-email-domains list is CC0 and held 9,222 domains on 10 October 2026; MailChecker is MIT and its list file held 56,513 domains after normalisation [10][11]. #
  • In StormDoor’s October 2026 held-out test, list-only matching caught 0% of withheld disposable domains and mail-server matching caught 53.5% of the 144 that were live (our own test) [12]. #
  • At StormDoor’s planned launch list prices (not yet available), a call would cost $0.76 per 1,000 on Starter and $0.40 per 1,000 on Scale, more than UserCheck at every volume compared on 10 October 2026. #

How do disposable email detectors work?#

A disposable email address is a mailbox on a service built for temporary use, such as a throwaway inbox that expires after minutes. Detectors use three signals:

  1. A list of known domains. Fast and free, but only as complete as its maintainers.
  2. Mail-server (MX) infrastructure. Many operators point hundreds of domains at the same mail servers, so an unlisted domain on a known server is suspect. See how disposable email infrastructure works and which mail servers disposable domains use.
  3. Domain age and registration data. Newly registered domains are a weak signal on their own. See disposable email and domain age.

Mailbox probing is a separate technique: the verifier opens an SMTP session to ask whether the mailbox exists. It answers “will this bounce”, not “is this throwaway”. The difference is covered in email validation vs verification.

Which option fits which use case?#

Free or self-hosted

Option Licence Size on 2026-10-10 Notes
disposable-email-domains [10] CC0 9,222 lines in disposable_email_blocklist.conf Additions need a screenshot of a generator using the domain. Maintainers say they do “basic checking” and cannot guarantee every domain is still disposable. Last commit 9 October 2026.
MailChecker [11] MIT 56,513 domains in list.txt after normalisation; README says “over 55 000” Libraries for several languages; format check included. Last commit 5 October 2026.
Kickbox open endpoint [6] Terms not verified n/a GET https://open.kickbox.com/v1/disposable/mailinator.com returned {"disposable":true} without a key on 10 October 2026. Limits and terms not checked.
DeBounce disposable endpoint [8] Terms not verified n/a GET https://disposable.debounce.io/?email=...; DeBounce describes a “realtime up-to-date list”; CORS enabled. Size not stated.

Pick these if all you need is a domain block list. They are free, auditable and add no vendor dependency. Their limits are the point of the next section. We also run a free disposable email checker for one-off lookups.

Cheapest per lookup

Option Entry At scale Free tier Response
UserCheck [1][2] Pro: $50 per month, 200,000 credits ($0.25 per 1,000) $500 per month, 3,500,000 credits ($0.143 per 1,000) 1,000 credits per month, 1 request per second Booleans and facts (disposable, relay_domain, mx, did_you_mean, role_account), no score

UserCheck describes detection as an “always up-to-date database of providers” and does not publish list size or method [1]. It does not probe mailboxes on the pages we read. Credits are per billing period. Its Pro plan keeps a 30-day request log [1]. If price per lookup is your main criterion, UserCheck beats every other option on this page, StormDoor included.

Bundled with mailbox verification

Option Entry price High-volume price Free tier Response
Abstract API email validation [3] Starter $17 per month, 5,000 requests ($3.40 per 1,000); Standard $37, Professional $39 at the same volume Up to 150,000 requests per month; per-1,000 price at the top not shown 100 requests per month, 3 per second is_disposable_email flag, quality_score (example 0.33), deliverability
Kickbox [5] $10 per 1,000 verifications $2,999 per 1,000,000 ($3.00 per 1,000) 100 Verification result; field list not re-verified
DeBounce [7][9] “From $0.00045 per check” ($0.45 per 1,000); tier not stated Not stated 100 credits Deliverable, risky, disposable or catch-all results
IPQualityScore [4] Plan prices not shown on pages we could read n/a “1,000 Free Lookups” disposable flag plus fraud_score, smtp_score, overall_score, deliverability, catch_all; default timeout 7 seconds

Abstract’s page says it “runs a live SMTP check without sending a message” and “flags disposable and catch-all addresses” [3]; its own sample marks a yopmail address DELIVERABLE with is_smtp_valid: true, so a deliverable result is not a disposable-free result. DeBounce charges 10 credits for catch-all validation and 20 for enrichment [7]. Choose these when you also need bounce prevention. Mailbox probing is something StormDoor does not do.

Bundled with other signup checks

Option What is bundled Price Response
StormDoor /v1/emails We make this Syntax, role account, typo, MX, disposable list, disposable mail-server matching, domain age, optional signup-IP checks Not yet available (waitlist). Planned launch pricing: Starter $19 per month for 25,000 credits ($0.76 per 1,000); Growth $99 for 200,000 ($0.495); Scale $399 for 1,000,000 ($0.40); 1 credit per call; planned one-time 5,000-credit trial; no free API plan Verdict (clean, suspect, block), findings with fixed severity and a docs page each, checks_run and checks_skipped
IPQualityScore [4] Email, IP and device signals under one key Not retrieved Score plus flags
UserCheck [2] Optional IP lookup on Gates requests (+2 credits, 3 total) See above Facts, no score

StormDoor has no customers yet, no SOC 2 report and no mailbox probing. It retains no request payloads and hosts in Frankfurt, which matters if you want content to stay in the EU. A call that fails returns an error envelope with no verdict; errors caused by StormDoor carry fail_open: true, so the caller can let the form proceed.

Why do static lists miss new disposable domains?#

A list is a record of past discoveries. Disposable operators register new domains faster than volunteers can add them, and many point them at the same mail servers. Only domains someone reported are blocked.

We measured this on our own list. The upstream sources StormDoor builds on total 61,733 domains. We withheld a random 20% (12,346 domains) and rebuilt the mail-server set from the other 49,387 so the matcher never saw the withheld ones, then screened the first 500 withheld domains [12].

List only List plus mail-server matching
Withheld domains sampled 500 500
Live domains (denominator) 154 144
Flagged 0 77
Recall 0.0% 53.5%

List-only recall is 0% by construction, because we removed those domains from the list. The test shows what a list misses when a domain it has not seen shares a mail server with listed ones. It does not show recall against real new operators.

Method#

Vendor facts come from each vendor’s own pages, read on 10 October 2026; plan names are given where the vendor published them. Per-1,000 figures are our arithmetic from published price and volume. The Kickbox and DeBounce endpoints were each called once with a known disposable domain. We did not test detection accuracy of any third-party service.

Our measurement [12], run by StormDoor on its own detector in October 2026: a seeded random 20% hold-out of the 61,733-domain version of the disposable-domain list, rules-only, Starter-plan checks, live DNS lookups, first 500 held-out domains screened. A domain counted as caught if the check flagged it; 57% of sampled hold-out domains no longer resolve and were excluded; 18 lookups failed or timed out in the second run and were also excluded. Limits: the sample is 500 domains from one list, it is our own test with no cross-vendor comparison, and run-to-run variation is about 3 points. The false-positive check used 339 hand-picked business, university and government domains: none flagged as disposable infrastructure, one flagged as a young domain (stormdoor.dev, correctly), and one flagged by the existing list (nus.edu.sg, an upstream false positive). A business on a small shared mail host that a disposable operator also uses would be a false positive this set cannot surface.

Sources#

  1. UserCheck, home and pricing, accessed 2026-10-10.
  2. UserCheck, Credits, accessed 2026-10-10.
  3. Abstract API, Email validation, accessed 2026-10-10.
  4. IPQualityScore, Email validation API, accessed 2026-10-10.
  5. Kickbox, Pricing, accessed 2026-10-10.
  6. Kickbox open endpoint, live request, 2026-10-10.
  7. DeBounce, Pricing, accessed 2026-10-10.
  8. DeBounce, Free disposable check API, accessed 2026-10-10.
  9. DeBounce, API documentation, accessed 2026-10-10.
  10. disposable-email-domains, accessed 2026-10-10.
  11. MailChecker, accessed 2026-10-10.
  12. StormDoor internal measurement, 2026-10; method described in this article; see also email.disposable_infrastructure.

Also see the email checker and MX lookup tools. Corrections: tell us at the address on the site and we will fix verified errors.

Try it on your own input

Disposable email checker

Open the disposable email checker/v1/emails docs

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Original dataHow disposable email services hide, and how shared mail servers give them awayUpdated 2026-10-10Original dataHow old are disposable email domains?Updated 2026-10-10Original dataWhich mail servers disposable email domains run onUpdated 2026-10-10ReferenceEmail validation vs email verification: what each one does to your usersUpdated 2026-10-10
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