Email Privacy Glossary

An email address created for short-term use and thrown away afterwards. It receives real messages, so it works for verification codes and confirmation links, but it is not meant to hold an account you plan to keep.

At PureTempMail: Each address is random, lives for 1 hour by default and can be extended up to 24 hours from creation. When it expires, the mailbox, its messages and attachments are deleted.

Informal name for a disposable address, borrowed from prepaid burner phones. People use it for one sign-up and then stop checking it.

Read more: What Is a Burner Email? A Plain Definition, Types and Myths

A permanent extra address that forwards to your real inbox. Unlike a disposable address, an alias keeps working, so you can still receive password resets, and you can switch it off if it starts attracting spam.

Read more: Temporary Email vs. Email Alias: Which One Fits the Sign-Up in Front of You

Adding a tag after a plus sign, as in [email protected], so mail still reaches [email protected]. It helps with filtering, but it hides nothing: anyone can delete the tag and reach your real address.

Read more: Gmail Aliases Explained: Plus Addressing, Dots and a Filter That Tracks Every Site

A domain setting that accepts mail for any local part, even one nobody created. Catch-all domains receive a lot of spam and make it impossible for senders to check whether an address really exists.

At PureTempMail: We do not run a catch-all. Our SMTP server asks the API whether the recipient is an active mailbox and rejects the message during the SMTP conversation if it is not.

Read more: How Does Temporary Email Work? One Message's Path Through Our Servers

Everything before the @ sign. The domain decides which server receives the message; the local part decides which mailbox on that server gets it.

A temporary inbox that anyone can open by typing its address. Some temp mail services work this way, which means a stranger who guesses or reuses the address can read your codes and reset links.

At PureTempMail: Our addresses are random and the inbox is opened with a private mailbox ID that is stored only in your browser. Knowing the address alone does not open the inbox.

Read more: Is Disposable Email Safe? A Threat Model for Temporary Inboxes

A mail service that accepts incoming messages but cannot send or reply. It removes the main way temporary addresses get abused, which is sending spam or harassment from an untraceable account.

At PureTempMail: PureTempMail is receive-only, on the web and in the Android app.

Simple Mail Transfer Protocol, the language mail servers use to hand messages to each other, usually on port 25. A delivery is a short conversation: the sender names the recipient, the receiver accepts or rejects, then the message is transferred.

A DNS record that tells the internet which server accepts mail for a domain. If a domain has no working MX record, mail sent to it cannot be delivered.

At PureTempMail: The MX records for our domains point at our own SMTP server, so no third-party mail provider handles your messages.

A notice that a message could not be delivered. A hard bounce means the address does not exist; a soft bounce is temporary, for example a full mailbox or a server that is down.

At PureTempMail: Mail sent to an expired address is rejected, so the sender receives a bounce rather than a silent loss.

An anti-spam technique where a server temporarily rejects mail from an unknown sender and accepts it when the sender retries a few minutes later. Legitimate servers retry; many spam tools do not. It is a common reason a verification email arrives late.

Read more: How to Sign Up Without Giving Your Real Email

A line each mail server adds when it passes a message on, recording where it came from, where it went and when. Read from bottom to top, the Received lines are the route a message took.

At PureTempMail: Our email header analyzer turns these lines into a timeline with the delay at each step.

A unique identifier the sending system gives each message. Mail clients use it to group replies into threads, and support teams use it to find a specific message in their logs.

A web standard that keeps one connection open so a server can push updates to the browser as they happen. Inboxes built on it show new mail without reloading.

At PureTempMail: Our web inbox and Android app both receive new messages over SSE.

Sender Policy Framework, a DNS record listing the servers allowed to send mail for a domain. A receiving server checks the connecting server against that list and records pass, fail, softfail or neutral.

DomainKeys Identified Mail, a cryptographic signature added by the sending server. The receiver fetches the public key from DNS and checks that the signed headers and body were not changed in transit.

A DNS policy that tells receivers what to do when a message fails SPF and DKIM alignment with the From domain: deliver it, send it to spam, or reject it. It is the main defence against spoofed sender addresses.

The address bounces are sent to, also called the envelope sender. It often differs from the visible From address, for example when a company sends newsletters through a mailing provider.

A header the receiving server adds with its verdicts on SPF, DKIM and DMARC. It is the quickest place to check whether a suspicious message really came from the domain it claims.

A tiny, usually invisible image in an HTML email. When your mail client loads it, the sender learns that the message was opened, when, and from which IP address.

At PureTempMail: Our viewer loads remote images, so pixels in messages you open do fire. The sender learns the disposable address was opened. It does not learn your real email address.

Read more: Email Privacy: What Opening a Message and Your Address Reveal

A sign-up flow that sends a confirmation link and only adds you to a list after you click it. It is the reason so many sites need a working inbox for just a few minutes.

A list of domains known to belong to temporary email services. Sites use it to refuse sign-ups from throwaway addresses, usually to limit trial abuse and fake accounts.

Read more: Why Do Websites Block Disposable Email? The Site Owner's Side

An incident in which a company's user data is exposed or stolen. Email addresses are among the most commonly leaked fields, which is why a real address used on many sites ends up on spam and phishing lists.

Read more: How to Check If Your Email Was in a Data Breach, and What to Do in the First Hour

A message that pretends to come from a trusted sender to make you click a link, open a file or hand over credentials. Checking the authentication headers and the real link target are the two fastest ways to spot one.