A Simple Breakdown of What Happens When You Hit “Send”

One picture is worth a thousand words — but let’s break it down in text!

Ever wondered what really happens when you send an email? Let’s walk through a simple version of how Alice’s email reaches Bob.

🛠 Step-by-Step: How Emails Travel Behind the Scenes

1️⃣ Alice logs into her Outlook email client (could be a mobile app or desktop program), writes a message to Bob, and hits “Send.”

➡️ The email first goes to Outlook's mail server using a protocol called SMTP (Simple Mail Transfer Protocol), which is used to send emails.

2️⃣ The Outlook mail server now needs to figure out where to deliver the email.

➡️ It uses the DNS (Domain Name System) to look up Bob’s email domain (like gmail.com) to find the address of Gmail's SMTP server.

3️⃣ Once the address is found, Outlook’s server sends the email to Gmail’s mail server — again using SMTP.

📦 Gmail now stores the message in its system, associating it with Bob’s account.

4️⃣ When Bob opens his Gmail app or webmail, the app contacts Gmail’s IMAP or POP server to retrieve new messages.

📥 IMAP (Internet Message Access Protocol) and POP (Post Office Protocol) are used to receive emails. IMAP is more common today because it syncs across multiple devices.

🧠 A Few Key Concepts:

  • SMTP = Think of it like the postal service — it picks up and delivers mail.
  • IMAP/POP = These are the inbox assistants — they fetch and organise mail for the recipient.
  • DNS = Like the internet’s phone book — it translates email domains into actual server addresses.

📌 Why This Matters:

Understanding how email systems work helps us appreciate how much tech is working quietly in the background — every time we send a simple “Hello.”

🔒 It also lays the foundation for understanding security (spam filters, phishing protection), scalability, and delivery reliability in large email systems like Gmail or Outlook.

This is just a simplified view — real-world systems are far more robust and complex. But I hope this sparks some curiosity! I’ll break down other components (like spam detection, message queuing, etc.) in future posts.

💬 Have any questions or want to dive deeper? Drop a comment!