Learn how email works
The protocols, records and tricks behind the mail you send and receive, explained plainly.
What is IMAP? How email syncs across devices
The protocol that keeps your mail on the server and in sync across every device you use.
SMTPWhat is SMTP? How email gets sent and delivered
The protocol that carries a message from your outbox to the recipient's mail server.
IMAP vs POP3IMAP vs POP3: which should you use?
Sync on every device or download to one: how the two ways of fetching mail compare.
POP3What is POP3? The download-and-delete email protocol
The older protocol that downloads mail to a single computer instead of syncing it.
SSL/TLS vs STARTTLSSSL/TLS vs STARTTLS: email ports 993, 465 and 587
The two ways mail apps encrypt their connection, and which port number goes with which.
SPFWhat is SPF? Sender Policy Framework explained
A DNS record that lists which servers are allowed to send mail for a domain.
DKIMWhat is DKIM? Email signatures explained
A digital signature on each message that proves which domain sent it and that it was not altered.
DMARCWhat is DMARC? Policies, alignment and reports
The policy that tells receiving servers what to do when mail claiming to be from a domain fails its checks.
BIMIWhat is BIMI? Brand logos next to email
A standard that shows a sender's verified logo next to its email, built on top of DMARC.
Email clientWhat is an email client? Apps, webmail and how they work
The app you use to read and send mail, and how it connects to your email provider.
Tracking pixelWhat is an email tracking pixel? How opens are tracked
The invisible image that tells a sender when, where and on what device you opened their email.
OAuthWhat is OAuth? Signing in to email without a password
How a mail app gets access to your account through the provider's own sign-in page, without seeing your password.
Email spoofingWhat is email spoofing? How fake senders work
Sending email that pretends to come from someone else, and the checks that make it harder.
PhishingHow to spot a phishing email: 8 signs to check
Concrete signs that a message is trying to trick you, and what to do when you find one.
Email headersWhat are email headers? How to read them
The hidden lines at the top of every message that record where it came from and how it got to you.
S/MIME vs PGPS/MIME vs PGP: email encryption compared
The two standards for end-to-end email encryption, and how their approaches to keys and trust differ.