Guide · Email aliases
Email alias: one address per site, all in one private inbox
An email alias is an extra address that delivers to an inbox you already have, so you never hand out your real address. Give every site its own alias and the one that starts getting spam tells you exactly who leaked or sold it. Mailfinity gives you unlimited aliases on your own domain or a free mailfinity.email subdomain, in one private inbox that flags leaks for you.
What is an email alias?
An alias is an address that isn't a mailbox of its own. Mail sent to it lands in a mailbox you already use. You can hand out as many aliases as you like and still read everything in one place.
Aliases come in three common forms: plus addressing (you+shop@gmail.com), an alias service that forwards to your personal inbox, or a catch-all domain where every address you make up just works.
Why use a different email for every site?
Your real address is the key to your accounts and the target of most phishing. Every signup that gets it is another place it can leak from. With one alias per site, a breach exposes an address you can throw away, not the one you use for your bank.
- A leak or a sale shows up on one address, so you know which company caused it.
- You can switch off a single address without touching the rest.
- Phishing stands out: a message claiming to be your bank that arrives at your newsletter address is fake.
How to find out who sold your email
For an address you already gave to dozens of companies, there is usually no way to tell who passed it on. Sites like Have I Been Pwned can show which known breaches included it, but not who sold it.
From today on, it is easy: give each company its own alias. When netflix@yourdomain starts receiving mail from a stranger, Netflix leaked or sold it. Mailfinity spots this automatically: mail from a sender that never wrote to an address before is flagged as an unfamiliar sender, and you can block that address in one click.
How Mailfinity aliases work
Mailfinity is a catch-all inbox. You never create an alias first: you make one up on the spot (github@, shop-2025@, anything) and it appears the moment mail arrives. There is no limit on how many you use.
Use your own domain with three DNS records, or claim a free mailfinity.email subdomain that works right away. The browser extension can even create a site-labelled alias for you in any signup form. Mail is kept apart from your personal inbox, not forwarded to it.
Plus addressing vs alias service vs Mailfinity
Three ways to give every site its own address, and where they differ.
| Plus addressing | Forwarding alias service | Mailfinity | |
|---|---|---|---|
| Hides your real address | No, it is right before the + | Yes | Yes |
| Survives a spammer cleaning the list | No, the +tag is easy to strip | Yes | Yes |
| Accepted by signup forms | Some forms reject the + | Yes | Yes |
| New address without setup | Yes | Depends on the service | Yes, any address just works |
| Where the mail goes | Your personal inbox | Forwarded to your personal inbox | A separate inbox, kept apart |
| Tells you who leaked it | You check the To: line yourself | You check the To: line yourself | Flagged automatically |
| Send and reply | Yes | Usually | Not yet, receive-only |
FAQ
What is an email alias?
An email alias is an extra address that delivers to an inbox you already have. It lets you give out different addresses, for example one per website, without creating a new mailbox for each.
How can I find out who sold my email address?
For an address you have used everywhere, you usually can't. From now on, give each company its own alias: if mail reaches that alias from someone else, that company leaked or sold it. Mailfinity flags this automatically as an unfamiliar sender.
Is plus addressing good enough?
It helps with filtering, but your real address is visible right before the +, spammers can strip the tag, and some signup forms reject it. A real alias on its own domain avoids all three.
How many aliases can I have with Mailfinity?
As many as you like. Every address on your domain or free mailfinity.email subdomain works without setting it up first.
Do I need my own domain?
No. Claim a free mailfinity.email subdomain and start using aliases right away. You can add your own domain next to it later.
What is the difference between an alias and a disposable email?
A disposable address usually expires after minutes or hours, so you lose access to the account it was used for. An alias stays yours: password resets keep working, and you can still block it the day it leaks.
Can I reply from an alias?
Not yet. Mailfinity is receive-only for now, built for signups, login codes and newsletters.
Get unlimited aliases in one private inbox
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