Simplelogin Vs Addy Io Vs Firefox Relay Email Alias Comparis

Email alias services have become essential tools for developers and power users who value privacy. Rather than giving out your primary email address to every service, you create aliases that forward emails to your inbox while hiding your real identity. This guide compares three popular options: SimpleLogin, Addy.io, and Firefox Relay — covering API capabilities, self-hosting options, pricing, and the privacy trade-offs each model involves.

Why Email Aliases Matter for Privacy

Every time you hand over a primary email address, you create a permanent link between your real identity and a service. If that service is breached, sold, or simply starts spamming, there is no clean way to disconnect. Email aliases break that link. When a particular alias attracts spam or a service gets compromised, you disable or delete the alias and the problem disappears without affecting your inbox or revealing your real address.

Beyond spam control, aliases limit cross-service tracking. Advertisers routinely share email lists and use address matching to build profiles across platforms. A unique alias per service makes this correlation much harder. For developers testing sign-up flows or working with sandboxed accounts, alias services also solve the “one email per account” problem neatly.

Service Overview

SimpleLogin

SimpleLogin was acquired by Proton in 2022 and now integrates with the Proton ecosystem. It offers both free and paid tiers, with premium features including unlimited aliases and custom domains. The service supports catch-all domains, SMTP forwarding, and PGP encryption. The Proton integration means SimpleLogin accounts can share authentication with Proton Mail, Proton VPN, and Proton Drive, giving privacy-conscious users a consolidated account management experience.

The free plan allows 10 aliases with basic forwarding. The premium plan, priced at around $30 per year, lifts the alias cap, adds custom domains, catch-all addressing, and API access. PGP encryption is available at both tiers, which distinguishes SimpleLogin from its competitors.

Addy.io

Addy.io (formerly AnonAddy) is an open-source email alias service that emphasizes privacy and self-hosting. You can use their managed service or deploy your own instance. The free tier includes 10 aliases, while paid plans expand this significantly. Addy.io provides a RESTful API accessible on all plan tiers and supports SMTP forwarding with custom domain integration.

Pricing starts around $12 per year for the Lite plan and $36 per year for the Pro plan, which adds unlimited shared domain aliases and higher bandwidth limits. Because the codebase is open-source, security researchers can audit it, and self-hosters get complete ownership over their data.

Firefox Relay

Mozilla’s Firefox Relay offers a free tier with 5 aliases and a paid Relay Premium at $0.99/month for unlimited aliases and phone number masking. It integrates naturally with Firefox but works across all browsers. The service focuses on simplicity rather than advanced features, making it the lowest-friction option for users already within the Mozilla ecosystem.

Firefox Relay lacks custom domains, SMTP sending, API access for advanced workflows, and self-hosting capability. It is a sensible choice for casual users who want basic alias functionality without configuration overhead.

Feature Comparison for Developers

Feature	SimpleLogin	Addy.io	Firefox Relay
Free Tier	10 aliases	10 aliases	5 aliases
API Access	Premium only	Yes (all plans)	Limited
Self-Hosting	No	Yes	No
Custom Domains	Premium	Yes	No
SMTP Forwarding	Premium	Yes	No
PGP Support	Yes	No	No
Open Source	Partial	Yes	No
Phone Masking	No	No	Premium
Catch-All Domain	Premium	Yes	No

API and Integration Examples

SimpleLogin API

SimpleLogin provides a Python SDK for interacting with their service:

# SimpleLogin Python SDK example
from simplelogin import SimpleLogin

client = SimpleLogin(api_key="your_api_key")

# Create a new alias
new_alias = client.create_alias(
    mailbox_id="your_mailbox_id",
    alias_prefix="newsletter"
)
print(f"Created alias: {new_alias.email}")

# List all aliases
aliases = client.get_aliases()
for alias in aliases:
    print(f"{alias.email} - {alias.enabled}")

Note that API access requires a premium subscription. Developers building tooling around SimpleLogin need to factor this into their workflow.

Addy.io API

Addy.io offers a more developer-friendly approach with full API access on all plans:

# Addy.io REST API example with curl
curl -X POST "https://app.addy.io/api/v1/aliases" \
  -H "Content-Type: application/json" \
  -H "X-Api-Key: your_api_key" \
  -d '{
    "email_format": "random",
    "domain_id": "your_domain_id",
    "recipient_id": "your_recipient_id",
    "description": "Newsletter subscription"
  }'

# Addy.io Python wrapper
import addyio

client = addyio.Client(api_key="your_api_key")

# Create a random alias
alias = client.aliases.create(
    domain="yourdomain.com",
    recipient="youremail@example.com"
)
print(alias.email)

# Enable/disable alias
client.aliases.toggle(alias.id, enabled=False)

Firefox Relay API

Firefox Relay has limited API access. You can manage aliases through their web interface or use the official Firefox Relay extension:

// Firefox Relay extension API interaction
browser.runtime.sendMessage(" Firefox Relay@relay.firefox.com", {
  type: "createRelayEmail",
  parentTabId: tabs[0].id
}).then(response => {
  console.log("Created alias:", response.email);
});

Self-Hosting Capabilities

For developers who want full control over their email forwarding infrastructure, Addy.io is the clear winner. You can deploy Addy.io on your own server using Docker:

# docker-compose.yml for Addy.io self-hosting
version: '3'
services:
  addy-api:
    image: addyio/addy-api:latest
    environment:
      - DATABASE_URL=postgresql://user:pass@db:5432/addy
      - APP_URL=https://your-domain.com
      - API_KEY=something_secure
    volumes:
      - ./data:/data
    ports:
      - "3000:3000"
    depends_on:
      - db

  addy-web:
    image: addyio/addy-web:latest
    ports:
      - "8080:80"
    environment:
      - API_URL=http://addy-api:3000

This approach gives you complete ownership of your alias data and eliminates monthly subscription costs after covering server expenses. You also gain the ability to audit every piece of code handling your email metadata.

Self-hosting does require a working mail server, MX records, and enough operational knowledge to maintain the stack. For users comfortable with server administration, this is the most private option available among the three services compared here.

Privacy and Data Retention Analysis

Understanding what each provider stores — and for how long — is central to evaluating the privacy trade-offs.

SimpleLogin’s privacy policy states they store forwarded email metadata (sender, subject line, timestamp) for operational purposes. The Proton acquisition means compliance with Swiss privacy law, which offers stronger protections than US or EU alternatives in some respects. PGP encryption, when enabled, ensures email content remains encrypted at rest and in transit.

Addy.io’s managed service logs are retained for a shorter period and can be viewed in the dashboard. For self-hosted deployments, log retention is entirely under your control. The open-source codebase allows independent verification of any claim about data handling.

Firefox Relay is subject to Mozilla’s privacy policy. Mozilla logs metadata about alias usage for product improvement and fraud prevention. The policy permits data sharing within Mozilla’s corporate structure. For users already accepting Mozilla’s terms through Firefox sync, Relay adds no meaningful new data exposure, but it is less private than the alternatives for someone starting fresh.

Practical Use Cases

Transactional Email Protection

When signing up for services that send transactional emails, create specific aliases:

# Generating aliases for different services
def create_service_alias(service_name):
    # With Addy.io catch-all, any prefix@yourdomain.com works automatically
    return f"{service_name}@my-custom-domain.com"

# Usage
github_alias = create_service_alias("github")
aws_alias = create_service_alias("aws")
print(f"Use {github_alias} for GitHub, {aws_alias} for AWS")

Development Workflow

For developers building applications that need email sending capabilities:

// Using aliases in development
const DEV_ALIASES = {
  signup: 'dev-signup@yourdomain.com',
  passwordReset: 'dev-passwordreset@yourdomain.com',
  notifications: 'dev-notifications@yourdomain.com'
};

function sendDevEmail(type, to) {
  // Route through appropriate alias
  const from = DEV_ALIASES[type];
  console.log(`Sending email from ${from} to ${to}`);
}

Threat Modelling Your Alias Strategy

Different threat models call for different tools:

Casual spam prevention: Firefox Relay covers this with minimal setup. You do not need API access or custom domains to keep spam out of your inbox.
Developer automation: Addy.io’s free-tier API access makes it the practical choice for scripted alias creation in CI/CD pipelines, integration tests, or tooling.
Proton ecosystem users: SimpleLogin integrates cleanly if you already use Proton Mail, letting you manage aliases directly from your inbox.
Maximum privacy / no third-party trust: Self-hosted Addy.io eliminates external dependencies entirely. You control the infrastructure, the logs, and the retention policy.

Frequently Asked Questions

Can I send email from an alias, not just receive? SimpleLogin and Addy.io both support sending from aliases (replying forwards correctly). Firefox Relay does not support outbound sending — it is receive-only.

What happens if the service shuts down? With SimpleLogin or Firefox Relay, your aliases disappear and services using them can no longer reach you. With self-hosted Addy.io, you own the infrastructure and aliases remain functional as long as you maintain the server.

Do alias services work with two-factor authentication emails? Yes. Forwarding is transparent to the receiving application. OTP codes, login links, and security alerts arrive in your inbox the same way direct emails do.

Are there GDPR implications for European users? SimpleLogin operates under Swiss law (similar in many respects to GDPR). Addy.io’s managed service operates under UK GDPR. Firefox Relay follows Mozilla’s US-headquartered policies with EU data processing agreements. Self-hosted Addy.io puts GDPR compliance entirely in your hands.

Which Service Should You Choose

SimpleLogin suits Proton ecosystem users and those who need PGP encryption. Addy.io is the right call for developers who want API access without a premium subscription, or anyone willing to self-host. Firefox Relay is best for non-technical users who want simple alias management integrated into their browser with minimal friction.

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