How Temp Mail Works: Technical Deep Dive

Temp mail looks simple — open a page, get an address, receive mail. But behind the scenes it involves DNS, SMTP, storage, and real-time push. This guide breaks down the technical pipeline.

Technical Architecture

1. Domain setup: service owns domains (like 215.im)
2. DNS/MX records: MX records point to the temp mail server
3. SMTP receiving: server receives mail via SMTP protocol
4. Storage: received mail stored temporarily
5. Web display: user views inbox via webpage
6. Real-time push (optional): WebSocket notifications
7. Expiry cleanup: old mail and addresses auto-deleted

DNS and MX Records

When you email abc@215.im, the sender's mail server queries 215.im's MX record:

215.im.  MX  10  mail.215.im.

This tells the sender: "mail for 215.im goes to mail.215.im" — where YYDS Mail's server listens.

SMTP Receiving

The sender delivers mail via SMTP. Simplified session:

[Sender] RCPT TO: <abc@215.im>
[YYDS]   250 OK
[Sender] DATA
[YYDS]   354 Start mail input
[Sender] Subject: Your code is 123456
         .
[YYDS]   250 OK: queued

YYDS Mail accepts all mail to 215.im (and verified custom domains) regardless of prefix — that's why any prefix works.

Storage

YYDS Mail uses Inbucket file storage + PostgreSQL for business data. Email content in filesystem, business data (accounts, quotas) in database.

Real-Time WebSocket Push

When the frontend connects via WebSocket:

1. Browser establishes WebSocket connection
2. Mail server broadcasts new mail via message hub
3. WebSocket service captures broadcast, pushes to the user's browser
4. Frontend renders new mail instantly — no refresh needed

This beats traditional temp mail's polling approach.

Expiry Cleanup

YYDS Mail runs scheduled cleanup:

• Free mailboxes: cleaned after session timeout
• Paid mailboxes: protected, not auto-cleaned
• Expired emails: deleted from filesystem

This prevents storage from growing infinitely.

Custom Domain Technical Details

When users point their domain's MX to YYDS Mail, mail to that domain is also received. YYDS Mail verifies ownership, adds the domain to the "accepted list." Technically identical to native domains — just different ownership.

FAQ

Can temp mail receive all emails? Standard SMTP yes. Some strict anti-spam systems may reject sending to temp mail domains.

Why do all prefixes work? The SMTP server is configured as catch-all — accepts all mail to the domain regardless of prefix.

How fast does mail arrive? Usually seconds. Depends on sender's server speed.

Want to try? Generate temp mail, or read what is temp mail for basics.