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Email address syntax: local part, @, domain, explained
Question: 001.006.001 · What is the syntax of an email address (local-part@domain)? · ~2:40
Model note: overlaps the pillar-001 "parts of an address" video, so this one goes one level deeper: the formal names, the DNS reality behind the domain, and the practical rule for choosing a sending address. RFC 5322 named once, deferred.
COLD OPEN
captain@tidalmail.com

One symbol splits every email address on Earth into exactly two jobs. Get either side wrong and your mail has nowhere to go. Let's take one apart properly.

⬡ dissect, the full address types itself out center screen, the @ pulses once
BEAT 1, the two-part syntax

Split at the @. Before it, captain, that's the local part, the name of one specific mailbox. After it, tidalmail.com, that's the domain, the server that receives mail for that mailbox. Local part, at, domain. That is the entire syntax of an email address.

⬡ dissect, the address slides apart at the @, "local part" label snaps under captain, "domain" label snaps under tidalmail.com
BEAT 2, the domain has to actually work (the real-world check)
Valid-looking is not the same as working.

Here's what matters if you send: the domain side has to work in DNS, the internet's phone book. When a mail server delivers to captain@tidalmail.com, it looks up tidalmail.com's MX records to find where the mail goes. No MX records, or broken ones, and that address can't receive mail, no matter how valid it looks. If you're debugging a dead address, check the domain's MX records first, that's where about ninety percent of address problems live.

⬡ record-cards, an MX record card flips up next to the domain and glows green with a checkmark, then a second take where the card flips up empty, flashes red, and the envelope drops off screen
BEAT 3, the local part rules (keep it simple)

The local part is where the rules get generous. The official spec, RFC 5322, allows dots, plus signs, even some special characters, and there's a whole video on exactly what's allowed, linked below. But allowed is not the same as accepted everywhere. So if you're choosing a sending address, keep it boring. hello@ and support@ work everywhere. Exotic characters will cause you nothing but headaches.

⬡ record-cards, three address cards stack in: hello@ with a green tick, support@ with a green tick, h!e#o$@ shakes and grays out
BEAT 4, the fun bit

And that @ symbol? Picked in 1971 by Ray Tomlinson for the first networked email, because it meant "at" and almost never showed up in people's names. In 2010 the Museum of Modern Art added it to its design collection. Two characters of punctuation, one of them is literally art.

⬡ title-card, a giant @ rotates in, "1971" stamps beside it, then a small museum frame draws itself around it
TAKEAWAY

Local part, at, domain. The local part names the mailbox, the domain is where the mail actually goes, and the domain only works if its MX records do.

⬡ dissect, the full address reassembles with both labels settling into place
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Next: exactly which characters are legal in an address, and which ones real inboxes actually accept. Subscribe, we're working through every email question one at a time.

⬡ end-card, Subscribe + Next: "What characters are allowed in an email address?" (001.006.002)
DESCRIPTION

Email address syntax, explained: every address is local-part@domain. The local part names the mailbox, the domain names the server that receives the mail, and the domain only works if its MX records exist in DNS. Covers what mail servers actually look up when they deliver, why a valid-looking address can still be undeliverable, the practical rule for choosing a sending address, and the 1971 story of how the @ symbol was chosen.

Next: What characters are allowed in an email address? → [001.006.002]

Full written guide → reviewmyemails.com/emailalmanac/…/email-address-syntax

#email #emailaddress #deliverability

CONNECTIONS
• next: 001.006.002 What characters are allowed in an email address?
• related: 001.006.003 Plus-addressing and tagging · 001.006.006 What are invalid addresses?
• vocab: local part, domain, MX record, DNS, RFC 5322 (named only; own video)