Temp mail services by domain count: a census of 224,884 throwaway domains

Counted by mail server, the biggest temp mail service runs 3,689 domains on servers named unstablemail.com; Dropmail (3,308) and generator.email (3,017) follow. We looked up the mail servers of all 224,884 domains on FFraud's throwaway list on November 12, 2026. Only 50,653 of them still name a mail server.

Disposable email providers are concentrated. Half of the listed domains on dedicated temp mail servers sit on ten server groups: 19,672 of 39,233, or 50.1 percent (FFraud count, November 12, 2026). The rest of the list uses ordinary mail platforms, names no mail server, gave no answer, or no longer exists.

#Which temp mail services run the most domains?

A domain names its mail servers in MX records, and a sender tries the most preferred one first. RFC 5321 puts it plainly: "Lower numbers are more preferred than higher ones." We grouped the listed domains by that preferred server. Servers under one domain name, or on one IPv4 address, count as one service.

1. unstablemail.com3,689
2. Dropmail3,308
3. generator.email3,017
4. wallywatts.com2,123
5. One address, 1,761 names1,761
6. beavis99.com1,312
7. Clean Temp Mail1,278
8. YOPmail1,224
9. mb5p.com1,173
10. birdzpt.com787

Source: FFraud count of its list (copy built November 3, 2026), November 12, 2026

Four of the ten carry a service's name: Dropmail, generator.email, Clean Temp Mail and YOPmail. For each of them, the domains the service offers, or its own domain, send their mail to those servers. The other six, such as the unstablemail.com and wallywatts.com servers, carry no service's name.

One service can hide behind many names. Dropmail's mail arrives at two IPv4 addresses under 19 server names, from mx.dropmail.me to mx.emlhub.com and mx.spymail.one. A check that compares server names sees 19 services. A check that compares addresses sees one.

The count is steep at the top and long at the bottom:

Most groups are tiny: 3,168 of the 4,161 receive mail for a single listed domain, and only nine for more than 1,000.

#How many domains do Guerrilla Mail, Mailinator and YOPmail use?

More than their menus show: Guerrilla Mail offers 11 domains, from sharklasers.com to spam4.me, yet its server receives mail for 26 listed domains, all 11 among them. Its home page also offers to receive mail for a customer's own domain, at $9.99 a year.

mail.tm's public API listed a single active domain, fldubai.com, created on October 30, 2026. FFraud's list already held it on November 3. The same server, in.mail.tm, receives mail for 89 more listed domains.

Mailinator takes domains from its subscribers by design. Its documentation describes a system built around "entire domain-inbox ownership", where subscribers get private domains: "you can use a Domain you provide or the system will provide one for you". On November 12, 256 listed domains sent their mail to Mailinator's servers.

YOPmail rotates in the open. Its alternate-domains page says "Websites keep blocking disposable email addresses from time to time", advertises a new daily domain and lets users add their own. Its servers received mail for 1,224 listed domains. temp-mail.org's FAQ says an address is valid "until the service changes the domain list".

#What surprised us: three in five listed domains no longer exist

On November 12, 2026, 136,180 of the 224,884 listed domains, 60.6 percent, no longer existed in DNS. Another 29,922 named no mail server. A further 3,881 published a null MX, the record by which a domain "announces that it accepts no mail" under RFC 7505. The last 4,248 gave no usable answer.

1. No such domain136,180
2. Dedicated temp mail servers39,233
3. No MX record29,922
4. Ordinary mail platforms11,420
5. No usable answer4,248
6. Null MX3,881

Source: FFraud count, DNS lookups of November 12, 2026

Five endings stand out: domains ending in .tk, .ml, .ga, .cf and .gq make up 25,729 entries, 11.4 percent of the list. On November 12, just 28 of them still named a mail server. Of the 85,101 .com domains, 30.1 percent did.

1. .com30.1%
2. .net27.5%
3. .org26.1%
4. .ru23.8%
5. .info16.5%
6. .us16.2%
7. .xyz14.9%
8. .site7.9%
9. .ml0.3%
10. .tk0.1%

Source: FFraud count, DNS lookups of November 12, 2026

The second surprise was one IPv4 address with 1,761 server names. Each of its domains names a server of its own, the word mail in front of the domain. A check of server names sees 1,761 servers with one domain each, yet all 1,761 names lead to that one address. Four more addresses carry 651, 227, 178 and 151 server names.

#What it means for someone defending a sign-up form

A list of domain names covers only the domains someone has already seen. Clean Temp Mail's domains page listed 1,301 domains on November 12, 2026. FFraud's list of November 3 held 1,212 of them, 93.2 percent. The other 89 all sent their mail to the same machine as the 1,212.

• Check the mail server's address as well as its name. FFraud's free email check answers detection_source: mx_ip when "the machine receiving the domain's mail also receives it for many confirmed throwaway domains". The email check documentation lists every value.
• Expect new domains every day. YOPmail advertises a new daily domain, and Tinyhost says its domains "are controlled by their owners, who can add/remove them at any time".
• Treat an unknown custom domain as a possible temp mail inbox. Guerrilla Mail, Mailinator and YOPmail all receive mail for domains their users bring.
• Judge the threat by machines. Three in five listed domains no longer exist, while ten server groups carry half of the domains on dedicated temp mail servers.

PyPI's administrators wrote in June 2024 that prohibiting known throwaway domains is "one of the most impactful mechanisms we currently have" against bot accounts. For code, see the guide to blocking disposable email sign-ups. An earlier FFraud study of throwaway mail servers found unstablemail.com, generator.email and wallywatts.com at the top of FFraud's own records too.

#How we counted, and how to repeat it

We downloaded FFraud's list of throwaway email domains, the copy built on November 3, 2026 at 21:33 UTC, with 224,884 domains. On November 12, 2026, we looked up the MX records of every domain through public DNS resolvers. Where none answered, we asked again with a longer wait.

For each domain we kept the server with the lowest preference number. We named each server's operator by its registrable domain, the part of a name that the Public Suffix List says people can register. Then we looked up the IPv4 addresses of all 11,570 preferred servers.

Servers on one address count as one service, as do two server names that serve the same domains together. Mail platforms that also serve many ordinary domains stay out of the ranking, by the rules FFraud's email check uses. Among them are Cloudflare's mail servers, Google and registrar forwarding. Cloudflare's proxy addresses and private address space never join two services.

Anyone can repeat the count:

1. Download the list from the open data page. The copy on GitHub was built on November 3, 2026, and is MIT licensed.
2. Look up each domain's MX records with dig +short MX example.com, or with the free MX lookup, and keep the lowest preference.
3. Group the servers by their registrable domain and by their IPv4 address.
4. Count the domains in each group.

A brand in our chart means the domains a service offers, or its own domain, send their mail to that group. DNS shows where mail goes. It does not show who owns a machine, so the other groups carry their server names. Every count holds for November 12, 2026.

#Questions people ask