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Guide

Email for sign-ups: how it actually works

One question sits behind every article here: which address to enter at sign-up so the form accepts it and the message arrives. This page is the general answer. The walkthroughs that follow add what each service does differently.

How sites tell disposable mail apart

The server does not know what you plan to do with the address, and cannot find out. It looks at the domain — in three ways, which fire at different moments.

  1. 01

    The domain’s MX record

    First and cheapest: has the domain declared where mail should be delivered. A domain without an MX record is rejected instantly, before any message is sent. This is what weeds out addresses invented in the form itself.

  2. 02

    Public disposable-domain lists

    The domain is checked against open, community-maintained lists of temp-mail services. A new disposable service lands on them within days of launching — which is why a free service cannot hide: its domain is public by definition, it *is* its shopfront.

  3. 03

    Reputation and deliverability

    Even past the first two checks, the message still has to arrive. That is the domain’s SPF, DKIM and DMARC, and its absence from blocklists such as Spamhaus.

None of the three checks is about an address being "temporary". All three are about the domain. So "which email will work" is really the question "which domain".

Four options and where each one ends

What people usually reach for when they need an address to sign up with.

OptionPriceLifetimeDomain check
Disposable mailfree10 minutes to a daydomain is on the public lists
A free provider mailboxfreewhile you keep signing inpasses, but often wants a phone number
Your own domain and mail serverfrom $10/year plus a serverwhile you keep renewingpasses, if everything is configured right
A mailbox on someone else’s configured domainfrom $0.006 per mailbox per yearthe term you choosepasses; the domain is configured and monitored

The difference between the first and the last is not "temporariness" — it is whether the domain is on the lists and how long the address lives. The price column is rarely what decides it; the last two are.

How to receive the mail

Which way suits you depends on how many addresses you have and who they belong to.

  • One address and you need a code — open the mailbox in the dashboard: the message is right there and the code is highlighted for copying.
  • The mailbox has been handed to someone else — webmail at /mail, signing in with the mailbox address and its own password, no dashboard access needed.
  • Many mailboxes, or handing them to a team — a mail client over IMAP: one server for every domain, port 993, SSL/TLS.

Mailboxes receive only. You cannot send from them — and for confirmations and codes you do not need to.

When the message does not arrive

  • Less than a minute has passed — delivery is sometimes delayed under load.
  • Check the Junk folder inside the mailbox: filters put first-contact mail to a fresh address there more often.
  • Check the address for a typo — copy it rather than typing it.
  • Requested the code again? Only the latest one works.
  • The form rejected the address outright — then nothing was ever sent: take an address on another domain from your order.

What it costs

Prices start at $0.006 per mailbox per year and drop 20% from a hundred, 35% from a thousand and 50% from ten thousand. The term is chosen at checkout — from one year to permanent, which is bound to the domain’s registration. The tiers differ only in how many mailboxes share a domain.

All tiers and terms