What is an email alias and how does it work?

An email alias is a forwarding address — a secondary address that receives emails and passes them on to your real inbox. The sender thinks they're emailing you at that address. Your real address never appears.

That's the whole idea. And it's more useful than it sounds.

How an email alias actually works

When someone sends an email to an alias address, a few things happen:

1. The email arrives at the alias address
2. A forwarding rule sends it on to your real inbox
3. It lands in your inbox — usually labelled with which alias it came through
4. The original sender never learns your real address

From your perspective, the email just appears in your existing inbox — Gmail, Outlook, Apple Mail, whatever you already use. There's nothing new to log into. No separate account to check.

From the sender's perspective, they sent an email to an address that received it. They have no way to tell it's an alias.

What's the difference between an alias and a separate email account?

This is the most common question. A separate email account — like a throwaway Gmail or a second Outlook address — looks similar on the surface but works very differently in practice.

A separate account requires you to log in to check it. You'll either miss emails or remember to check it regularly. If you're signing up to something sketchy, it works — but for anything you actually want to receive, it's annoying. And eventually you abandon it, miss something important, and lose access.

An alias forwards everything straight to your real inbox. You don't change your workflow at all. You still use the email app you already use. You just give out a different address on the way in.

Why would you want an email alias?

Protecting your real address from spam

Every time you hand over your real email address — to a retailer, a sign-up form, a competition, a forum — you're taking a risk. Your address might get sold to marketers, leaked in a data breach, or scraped by bots.

Once your real address is on a spam list, it tends to stay there. Unsubscribe links often just confirm the address is active, which makes things worse. Filtering helps, but it's reactive.

An alias stops the problem before it starts. You give out the alias. If it starts receiving spam, you delete it. The spam stops immediately and permanently — the sender gets a bounce, not another inbox to find.

Knowing who's selling your data

If you use a unique alias for each service, you can trace exactly where a spam email originated. Got unwanted marketing from a company you've never heard of? Check which alias it arrived on. That tells you which company sold or leaked your data — even if they deny it.

Protecting against data breaches

Data breaches are common. Most major retailers, social networks, and online services have experienced at least one. If your real email address is in a breach, it can end up in credential-stuffing attacks — automated tools that try your email and leaked passwords across hundreds of other sites.

Aliases don't fully solve this, but they reduce your exposure. If a breach happens at a site where you used an alias, only the alias is leaked — not the address tied to your bank, your identity documents, or your password manager.

Separating different areas of your life

Some people use aliases purely for organisation — one address for shopping, one for work sign-ups, one for newsletters. Everything still lands in the same inbox, but the labels make it easy to filter and manage.

Random aliases vs custom aliases

There are two common alias formats.

Random aliases are generated automatically — a string of letters and numbers at a domain you control or subscribe to. They're harder to guess, which means they're more private. Nobody can reverse-engineer who you are from the address. Services like Privify generate these for you instantly.

Custom aliases let you choose the local part of the address. This can be useful if you want something memorable, but it's less private — and if you use something obvious, the alias can sometimes be guessed or brute-forced by determined spammers.

For most privacy use cases, random aliases are the right call.

Can you reply from an alias?

This depends on the service. Some alias providers support outbound replies that appear to come from the alias address. Others — including simpler services — are receive-only.

For many use cases, receive-only is fine. If you sign up to a service, receive their emails, and occasionally log into their site to interact — you never need to reply by email at all. For cases where you need two-way communication with a contact who only knows your alias, outbound support matters more.

Are email aliases the same as catch-all addresses?

Not quite. A catch-all address receives everything sent to a domain, regardless of what the local part says. So if you own a domain, you could set up a catch-all and receive emails sent to any made-up address at that domain.

Aliases are more controlled — each one is explicitly created and can be individually paused or deleted. Catch-alls are simpler to set up if you own a domain, but harder to manage and easier for spammers to flood.

How to get an email alias

There are a few routes:

• Your existing email provider — Gmail lets you add a + modifier (e.g. yourname+shopping@gmail.com), but this isn't a real alias — the base address is still visible, and many sites strip the + part
• A dedicated alias service — services like Privify, SimpleLogin, or addy.io give you proper aliases with no connection to your real address
• Your own domain — if you own a domain, you can set up forwarding rules directly. More control, but more setup

The Gmail + trick is better than nothing, but it's not private. Anyone who sees the alias can strip the + part and know your real address. A proper alias service generates an address with no visible link to you at all.

The bottom line

An email alias is one of the simplest, most practical privacy tools available. It costs nothing to understand, requires minimal setup once you have a service in place, and it fundamentally changes your relationship with online sign-ups — from handing over something permanent to handing over something disposable.

Your real email address is tied to your identity, your recovery options, your bank, your employment. It's worth protecting. An alias means you never have to hand it to anyone you're not certain you trust.