TL;DR: A +tag alias is a free label on your Gmail address. A second account is a whole separate inbox. A custom-domain address (via Send mail as) is a branded you@yourdomain.com you send and receive from inside your existing Gmail - the one most people actually want, and it does not need Workspace.
The three kinds of "alternate address"
| Type | Looks like | Best for |
|---|---|---|
| +tag alias | you+shop@gmail.com | Filtering, signups |
| Second account | another@gmail.com | A fully separate inbox |
| Custom domain | you@yourbrand.com | A professional, branded address |
Option 1: A +tag alias (same account)
Add a + and any word to your existing address - you+newsletter@gmail.com - and it still lands in your inbox. Free, instant, and great for filters and spotting who sold your address. The limit: it is still your @gmail.com, so it is not a separate identity and not brandable.
Option 2: A second Gmail account
Create another Gmail account and add it to the app for a genuinely separate inbox. Good for cleanly splitting two identities - but it is another inbox to check and log into, and it is still an @gmail.com address, not your own domain.
Option 3: A custom-domain address (Send mail as)
This is the branded one: you@yourbrand.com, sent and received from inside the Gmail you already use. It needs two pieces - receiving at your domain, and Gmail's "Send mail as" with an SMTP relay for sending - and, crucially, no Google Workspace. The full setup is in the Cloudflare Email Routing + Gmail Send As guide.
Personal Gmail alias vs. custom-domain send-as
These two get confused constantly, so here is the difference that matters:
- Personal alias (+tag): zero setup, but the recipient still sees a Gmail address, and you cannot use your own domain. Fine for you; not for clients.
- Custom-domain send-as: a little setup, but the recipient sees
you@yourbrand.com, replies come back to you, and - done right, with aligned DKIM - there is no "via" label. This is what looks professional.
If the address will ever be seen by a customer, you want custom-domain send-as.
Which one to pick
- Just organizing signups? → +tag alias.
- Want a totally separate personal inbox? → second account.
- Want a professional, branded address? → custom-domain send-as.
The easy way to a custom-domain address
If you land on the custom-domain option, the manual setup is real work and the authentication records are easy to get wrong. SendMailAs handles all of it:
- Routing, SMTP credentials, and SPF/DKIM/DMARC configured automatically - about 5 minutes, no DNS expertise.
- DKIM aligned to your domain, so mail lands in inboxes with no "via" label.
- Unlimited addresses and domains, inside your existing Gmail. First domain free, $29/year for unlimited.
Frequently asked questions
It can mean three different things: a +tag/dot alias of your existing address (free, same inbox), a separate Gmail account you add to the app, or a custom-domain address you add via 'Send mail as' so you can send and receive as you@yourdomain.com. Which one is right depends on whether you want a label, a separate mailbox, or a branded address.
A personal Gmail alias (the +tag trick) is just a label on your @gmail.com address - you cannot change the domain and it is not private about being a Gmail account. Custom-domain send-as adds a real address on your own domain (you@yourbrand.com) that you can send from and receive at inside the same Gmail. For anything client- or business-facing, custom-domain send-as is the one you want.
Yes. Gmail's 'Send mail as' works on a free personal account. For a custom-domain alternate address you also need to receive mail at the domain and provide SMTP credentials to send - which you can wire up manually or automate with SendMailAs. No Workspace subscription is required.
Gmail lets you add multiple 'Send mail as' addresses and pick which one to send from per message. With a catch-all on your own domain you can receive at unlimited addresses. SendMailAs supports unlimited addresses and domains on the $29/year plan.
A branded address, in your Gmail
Send and receive as you@yourdomain.com without a new inbox or a Workspace bill. SendMailAs sets it up in about 5 minutes. First domain free.