Email Forwarding Services Compared - Cleanbox vs ImprovMX vs ForwardEmail vs Cloudflare vs SimpleLogin

You have a custom domain and want email forwarded to your existing inbox. Several services do this, but with very different feature sets, privacy models, and pricing. Some are pure forwarders. Others add spam filtering, contact management, or alias-based privacy on top.

This guide compares five popular email forwarding services so you can pick the right one for your situation.

Quick comparison

Cloudflare Email Routing

Cloudflare Email Routing is completely free and does exactly one thing: forward email from your custom domain to an existing inbox. If your domain is already on Cloudflare, setup takes about 2 minutes — add a routing rule, verify the destination, and you are done.

There is no spam filtering, no contact management, no alias management interface, and no sending capability. It is a DNS-level forwarding rule, nothing more.

Best for: People who already use Cloudflare for their domain and want the simplest possible free forwarding. If spam becomes a problem, your destination inbox''s filter is your only defense.

Limitation: No spam filtering at all. SPF alignment issues can cause forwarded emails to be flagged by the destination provider.

ImprovMX

ImprovMX is a straightforward forwarding service with a clean interface. Point your MX records to ImprovMX, create aliases, and emails are forwarded to your destination. The premium plan adds SMTP sending, so you can send email from your custom domain address through their servers.

Best for: People who want simple forwarding with the option to send from their domain. The SMTP sending feature is the main differentiator — it makes ImprovMX a lightweight custom domain email solution.

Limitation: No spam filtering whatsoever. Every email that arrives at your domain is forwarded, including spam. You rely entirely on your destination provider''s filter.

ForwardEmail

ForwardEmail is an open-source email forwarding service. It includes basic SpamAssassin filtering, supports unlimited aliases on the free tier, and offers SMTP sending on paid plans. The open-source codebase means you can self-host it if you have the technical skills.

Best for: Privacy-conscious users who value open source and want a budget-friendly option. The free tier is the most generous of any service in this comparison.

Limitation: SpamAssassin filtering is basic compared to modern spam detection. The self-hosted option requires significant technical knowledge.

SimpleLogin (Proton)

SimpleLogin was acquired by Proton in 2022 and is now part of the Proton ecosystem. It focuses on email alias privacy — create random or custom aliases that forward to your real inbox. Available as a standalone service or bundled with Proton Unlimited.

For a broader comparison of how Proton''s approach differs from dedicated alias services, see our Proton Mail vs email aliases article.

Best for: Users already in the Proton ecosystem who want aliases integrated with their Proton Mail, VPN, and password manager. The Proton Unlimited bundle ($10/mo) includes SimpleLogin Premium alongside all other Proton services.

Limitation: No spam filtering, no contact management, no advanced rules. Custom domains require the premium plan. Best value only if you use other Proton services.

Cleanbox

Cleanbox goes beyond forwarding. Every inbound email is processed through a multi-layered spam detection pipeline (Rspamd with Bayes classifier, AI classification, and crowd-sourced sender reputation) before reaching your inbox. Contacts are automatically categorized, senders can be blocked or whitelisted, and Shield adds rate limiting, delivery scheduling, and sender whitelisting per alias.

For businesses with existing email infrastructure, Cleanbox Relay acts as an inbound MX gateway — filtering spam, viruses, and threats before forwarding clean messages to your mail server via SMTP.

Best for: People who want forwarding plus serious inbox protection. Businesses that need inbound filtering for existing addresses with virus scanning (ClamAV) and DNSBL blacklist checking.

Trade-off: Cleanbox aliases are receive-only — no sending from your alias address. If outbound sending from your custom domain is essential, pair Cleanbox with Gmail''s "Send as" or use ImprovMX/ForwardEmail for sending alongside Cleanbox for receiving and filtering.

Which service for which situation?

The honest take

If you just need email forwarding and trust your destination provider''s spam filter, Cloudflare (free), ForwardEmail (free/cheap), or ImprovMX (if you need sending) are simpler and cheaper options. They do forwarding well and nothing more.

If spam is an actual problem for you, or you want to control who can email your aliases, when they can reach you, and how their messages are handled, Cleanbox adds layers that pure forwarders do not have. It is a different category of service — forwarding is just one part of what it does.

For a step-by-step guide to setting up any of these services with your domain, see Custom domain email: the complete guide for small businesses. If you are experiencing SPF issues with forwarded email, our SPF and SRS troubleshooting guide explains the fix.