Every time you sign up for a service with your real email address, you’re creating a permanent link between your identity and that company. Email aliasing breaks this link — each service gets a unique, disposable alias that forwards to your real inbox. If a company is breached or sells your data, you just delete that alias.

How Email Aliasing Works

An alias service provides you with unlimited unique email addresses (e.g., [email protected]). When someone sends email to that alias, it’s forwarded to your real inbox. When you reply, the reply goes through the alias — the recipient never sees your real address.

When an alias starts receiving spam or you no longer need it, you disable or delete it without affecting anything else.

SimpleLogin (Best Overall)

SimpleLogin (simplelogin.io) was acquired by Proton in 2022. Open-source, self-hostable, and feature-rich.

Free tier: 10 aliases, 1 mailbox, limited bandwidth Premium ($4/month or included with Proton Unlimited): unlimited aliases, custom domains, multiple mailboxes

Setup:

Create account at simplelogin.io (or link your Proton account)
Install the browser extension (Chrome, Firefox, Safari)
When filling in an email field, click the extension → Create alias
A unique alias is created and copied for that site

The extension auto-suggests aliases when it detects email input fields.

Key features:

PGP encryption for forwarded emails
Custom domains (use your own domain for aliases)
Reply from alias (replies route through SimpleLogin)
Alias subdomain per alias (unlimited variety)
Self-hostable with Docker

Addy.io (Best for Power Users)

Addy.io (formerly anonaddy.com) is open-source and offers the most generous free tier.

Free tier: 10 shared domain aliases, unlimited subdomains Lite ($1/month): 50 shared aliases Pro ($3/month): unlimited everything

Unique feature: catch-all subdomain aliases — any email sent to [email protected] forwards to you, without pre-creating aliases. Useful for quick signups without opening the app.

# Sign up for a test: [email protected] goes to your inbox
# Shop at example.com → use [email protected]

Self-hostable:

git clone https://github.com/anonaddy/anonaddy
# Follow Docker Compose setup in docs

Apple Hide My Email (iPhone/Mac Users)

Apple’s built-in alias service — available to iCloud+ subscribers ($1/month for 50GB plan):

Safari auto-suggestion: when signing up on a website in Safari, Apple suggests “Hide My Email”
iCloud Settings → Hide My Email: manage all aliases
Aliases are @privaterelay.appleid.com addresses
Unlimited aliases, but no custom domains

Best for Apple ecosystem users who want no additional apps.

Firefox Relay

Mozilla’s alias service — 5 free aliases, premium for unlimited.

Integrated into Firefox browser
Firefox Premium Relay: includes phone number masking too
Simpler than SimpleLogin but fewer features

Choosing the Right Alias Strategy

Per-service aliasing (recommended):

Create a new alias for every service: [email protected], [email protected]
Label each alias in SimpleLogin/Addy.io with the service name
When an alias receives spam, you know exactly which company leaked/sold your email

Catch-all for low-risk signups (Addy.io):

Use [email protected] without creating aliases first
Fast, but slightly easier to guess your alias pattern

Never use your real email for:

Data broker sites
Contest entries
Software trials
Any service you’re unsure about

Managing Your Aliases

Both SimpleLogin and Addy.io have dashboards showing:

How many emails each alias received
Spam ratio per alias
Which aliases are most active

Signs an alias has been sold: you receive marketing email from companies you didn’t sign up with using that alias. Disable the alias and know exactly which company sold your data.

Custom Domains

Both SimpleLogin and Addy.io support custom domains (e.g., @privacy.yourdomain.com). Benefits:

More memorable aliases
Aliases survive if you leave the service (point domain to new provider)
Unlimited variety: [email protected], [email protected]

Add a custom domain:

Buy a domain from a privacy-respecting registrar (Njalla, Porkbun)
Add the domain in SimpleLogin → follow DNS setup
Create or catch-all all aliases on that domain

Email aliasing costs $4/month or less and is one of the highest-ROI privacy investments available. Once set up, the habit of creating a new alias per site becomes automatic.