SMTP, IMAP, POP3: What Really Happens When You Hit Send?

Email is a fascinating technology. It is one of the few protocols from the 70s that still survives today, almost unchanged, at the heart of our global economy.

When you send a WhatsApp message, you use a proprietary black box. You depend entirely on Meta's servers. When you send an email, you use a federated system. You can be on Gmail and write to someone on Outlook, who replies to someone on JunkMail. It is the digital equivalent of the traditional post office: universal and standardized.

But what really happens in the cables when you press "Send"? It's a complex choreography between three main actors: SMTP, IMAP, and POP3.

Act 1: The Postman (SMTP)

SMTP = Simple Mail Transfer Protocol.

This is the workhorse of email. It's the one moving mail from point A to point B.

The Scenario: You (Alice) write to Bob (bob@example.com).

1. Sending: Your computer connects to your provider's SMTP server (e.g., smtp.gmail.com) and says: "Here, I have this message for Bob".
2. Relay: Gmail's SMTP server looks at the recipient's address. It sees @example.com. It queries the internet directory (DNS) to ask: "Who handles mail for the domain example.com?" (This is the MX record).
3. Delivery: Gmail's server connects to example.com's SMTP server and delivers the package.

That's it. SMTP's job stops there. It dropped the letter in the mailbox of Bob's building. It doesn't know if Bob read it, nor if Bob is there.

Act 2: Retrieving Mail (POP3 vs IMAP)

Once the message arrives on Bob's server, it is stored on a hard drive waiting. For Bob to read it on his phone, he must go get it. This is where two schools clash.

The Old School: POP3 (Post Office Protocol)

Imagine you go to the Post Office. You ask for your mail. The clerk gives you all your letters. The Post Office box is now empty. You go home with your letters.

• Advantage: You can read offline. It doesn't take up space on the server.
• Major Disadvantage: If you pick up your mail on your phone, it is downloaded and deleted from the server. When you get home to your computer in the evening, the box is empty. Devices are not synchronized.

The Modern School: IMAP (Internet Message Access Protocol)

Now imagine you didn't take the letters. You go to the Post Office, you make photocopies, or you read on the spot. The original always stays in the Post Office box.

If you read a message on your phone, your phone tells the server: "Mark this message as Read". When you open your computer, the server tells it: "This message has already been read".

• Advantage: Perfect synchronization between all your devices (PC, Tablet, Mobile).
• Disadvantage: You depend on server storage space (that's why Google sells Google One storage).

Where Does JunkMail Fit In?

JunkMail is a hybrid creature optimized for privacy.

1. Reception (SMTP): We use an ultra-lightweight home-brewed SMTP server (Haraka). When Amazon sends you an email, our server accepts it.
2. Storage: Instead of putting it in a classic file, we process it, remove trackers (pixels), and store it in a database.
3. Reading: We do not offer classic POP3/IMAP (for now). We offer a REST API and WebSockets. This is a modern evolution of IMAP. Instead of synchronizing heavy folders, your browser receives an instant notification (Push): "New message!".

The Philosophy Moment: The Resilience of Federation

Why haven't we replaced email with something better? Slack, Teams, WhatsApp tried. But email resists because it belongs to no one. If Gmail closes tomorrow, email will continue to exist. If Slack closes, your messages are lost.

Understanding SMTP is understanding Internet freedom. It's the ability to set up your own server in your garage and be able to write to the President without an intermediary.

Conclusion

The next time you configure your email box and are asked "POP or IMAP?", you'll know what to answer.

• POP is for digital hermits with a single computer.
• IMAP is for the connected multi-screen citizen.
• JunkMail is for those who want to enjoy the system without suffering the nuisances.

Take back control of your protocols. Create your JunkMail account.