Key concepts: aliases, mailboxes, relay, and shield
Overview
Cleanbox is built around a few core concepts that work together to keep your inbox clean and secure. This article explains each one so you can get the most out of the platform.
Aliases
An alias is a unique email address that forwards incoming mail to your real inbox. Instead of giving out your personal email address, you hand out aliases — keeping your real address private and protected.
Cleanbox supports three alias formats:
- Random — a randomly generated address on your Cleanbox domain (e.g. x7k9m2@cleanbox.me)
- Custom name — a human-readable name you choose (e.g. shopping@cleanbox.me)
- Domain-based — aliases on your own custom domain, if you’ve connected one
Aliases are receive-only — you cannot send or reply from them. Each alias has its own spam threshold, so you can be strict on some and lenient on others. If an alias gets compromised or starts receiving too much junk, disable it with one click. The source of the leak is immediately obvious.
Mailboxes
A mailbox is the real email account where your aliases deliver mail to — your Gmail, Outlook, iCloud, or any other provider that supports IMAP.
You connect a mailbox by entering the IMAP server details and credentials manually. Most providers require an app-specific password rather than your main account password (Cleanbox does not use OAuth).
Once connected, every alias you create can be pointed at that mailbox. Clean mail arrives in your inbox as if it were sent directly to you.
You can also create virtual mailboxes. These don’t deliver via IMAP — instead, mail is processed, filtered, and stored within Cleanbox itself. This is useful if you want to monitor an alias without cluttering a real inbox.
Relay
Relay is designed for businesses and teams that already have their own mail server and existing email addresses. Instead of creating aliases, you point your domain’s MX records to Cleanbox. All inbound email for that domain flows through Cleanbox first, gets filtered, and is then forwarded to your mail server via SMTP.
Your existing addresses keep working exactly as before — your users don’t need to change anything. Cleanbox sits transparently in front of your infrastructure.
Relay filtering includes:
- Rspamd spam analysis with per-address thresholds
- ClamAV virus scanning on attachments
- DNSBL blacklist checks (Spamhaus, Barracuda, SpamCop)
- SPF, DKIM, and DMARC validation
- SRS (Sender Rewriting Scheme) to preserve deliverability when forwarding
Relay is available on the Advanced ($35/mo) and Enterprise ($100/mo) plans only.
Shield
Shield is a per-alias protection layer that gives you fine-grained control over what gets delivered. It includes three features:
Rate Limiter
Caps how many emails a single contact can send you within a time window. Useful for stopping mailing-list floods or a sender that’s gone haywire.
Delivery Snoozer
Defines time windows when email is actually delivered. For example, set an alias to only deliver Monday–Friday between 9:00 and 17:00. Messages arriving outside the window are held and delivered when it opens again.
Gatekeeper
Switches an alias to whitelist-only mode. Only contacts you’ve explicitly approved can reach you — everyone else is rejected. Perfect for aliases where you want absolute control.
Other features worth knowing
- Filters — user-defined rules that automatically sort, tag, block, or redirect email based on conditions you set (sender, subject, headers, and more).
- Contacts — Cleanbox automatically categorises senders into states like trusted, neutral, or blocked. You can override these at any time to fine-tune delivery.
- Cloud Storage — automatically extracts and stores attachments from incoming email, so you can browse and download them separately without digging through your inbox.
