Email Forwarding Services Compared: Cleanbox vs ImprovMX vs ForwardEmail
You have a custom domain and want email forwarded to your existing inbox. Three services do this, but with very different feature sets. ImprovMX is pure forwarding. ForwardEmail is open-source forwarding. Cleanbox is forwarding plus spam filtering, contacts, and protection.
Quick comparison
| Cleanbox | ImprovMX | ForwardEmail | |
|---|---|---|---|
| Core function | Forward + filter + protect | Forward | Forward |
| Spam filtering | Yes (Rspamd, Bayes, crowd-sourced) | No | Basic (SpamAssassin) |
| Virus scanning | Yes (ClamAV, relay) | No | No |
| Contact management | Yes | No | No |
| Filters/rules | Yes (10 components, regex) | No | Basic |
| Shield (rate limit/schedule) | Yes | No | No |
| Send from domain | No (receive-only) | Yes (SMTP credentials) | Yes (SMTP) |
| Catch-all | No (per-alias only) | Yes | Yes |
| Open source | No | No | Yes |
| Free tier | 3 aliases, 50/week | 1 domain, 25 aliases | Unlimited aliases |
| Paid | From $5/mo | From $9.99/mo | From $3/mo |
ImprovMX
ImprovMX does one thing well: email forwarding for custom domains. Point your MX records to ImprovMX, create aliases, and emails are forwarded to your destination address. No spam filtering, no contact management, no frills. Their premium plan adds SMTP sending, so you can send email from your custom domain address.
Best for: People who want the simplest possible forwarding setup and are happy with their email provider's spam filter. Good if you need outbound sending on your domain.
ForwardEmail
ForwardEmail is an open-source email forwarding service. It supports unlimited aliases for free, includes basic SpamAssassin filtering, and offers SMTP sending on paid plans. The open-source code means you can self-host it.
Best for: Privacy-conscious users who value open source. Good budget option for basic forwarding with some spam protection.
Cleanbox
Cleanbox goes beyond forwarding. Every email is processed through a full spam detection pipeline (Rspamd + Bayesian classifier + crowd-sourced reputation) before forwarding. Contacts are categorized, senders can be blocked or whitelisted, and Shield adds rate limiting and delivery scheduling.
Best for: People who want forwarding plus inbox protection. Businesses that need Relay for existing addresses with virus scanning and blacklist checking.
Trade-off: Cleanbox aliases are receive-only — no sending from your domain address. If you need to send email from your custom domain, ImprovMX or ForwardEmail are better choices. Alternatively, use Cleanbox for receiving and configure Gmail's "Send as" with your domain's SMTP for outbound.
The honest take
If you just need email forwarding and already trust Gmail's or Outlook's spam filter, ImprovMX or ForwardEmail are simpler and cheaper. If spam is a real problem for you, or you want to control who can email your aliases (and when, and how often), Cleanbox adds layers that pure forwarders do not have.
For a detailed setup guide, see Custom Domain Email: The Complete Guide for Small Businesses.
