Guide
How to send email as your domain (SMTP reply-as)
Forwarding gets mail in. Reply-as lets you send mail out from [email protected], so recipients see your professional address instead of your personal inbox. You do it with a set of SMTP credentials and your existing mail app.
Why reply-as matters
If you only forward, replying from your Gmail or Outlook inbox reveals your personal address — which looks unprofessional and breaks the illusion of a real domain mailbox. Reply-as routes your outgoing mail through an authenticated SMTP server for your domain, so the From address is your domain and the message is properly signed.
What you need first
A verified domain with DKIM in place. Each alias has its own SMTP username and password, shown on the alias screen.
Set it up in Gmail
- Copy the alias SMTP username, password, host, and port.
- In Gmail: Settings → Accounts and Import → Send mail as → Add another email address.
- Enter your domain address, uncheck "Treat as an alias" if you want it to behave as a separate identity, and continue.
- Enter the SMTP host, port, username, and password. Send the verification.
- The confirmation email forwards to your inbox — click the link. Optionally make it your default sender.
Set it up in Outlook and Apple Mail
Any client that supports adding an SMTP sending account works the same way: add a new account or identity, enter your domain address, and supply the SMTP host, port, username, and password from the alias. Use the submission port your client recommends and enable STARTTLS/SSL.
Deliverability notes
- Keep SPF, DKIM, and DMARC in place — they're what let your domain mail pass authentication at the recipient.
- Treat the SMTP password like any credential. If it leaks, rotate it from the alias screen.
- Sending volume is meant for normal correspondence, not bulk campaigns.