SpamSieve
SpamSieve is a macOS application that adds spam filtering to compatible Mac mail programs.
What SpamSieve is
SpamSieve is a macOS application that adds spam filtering to compatible Mac mail programs. Its Bayesian filtering adapts to the mail received and can handle accounts from any provider or host without extra charges for additional addresses or devices. Users can create allowlists and blocklists based on message headers or body text, including regular expressions. The app decodes encoded messages and inspects attachments for spam content, and it can use macOS Contacts so messages from contacts are not marked as spam. Supported programs include Apple Mail, Airmail, GyazMail, MailMate, MailMaven, Outlook and other listed Mac clients. Browser-based services such as Outlook Live are unsupported except through those clients. Mail data stays on the Mac; account login access is not required and data is not transmitted elsewhere. SpamSieve requires macOS 10.13 or later and a compatible mail program. It does not run on iOS, although a Mac can filter mail synchronized to iPhone or iPad through IMAP or Exchange.
Good
- Bayesian filtering adapts to received mail
- Works across mail providers and accounts
- Custom header and body rules support regular expressions
- Attachment inspection included
- Mail data stays on the Mac
Watch out
- No free plan
- Requires macOS 10.13 or later
- Browser-based Outlook Live is unsupported
- Does not run on iOS
Who it suits
It suits Mac users with a compatible mail client who want adaptive spam filtering and attachment inspection. It is not suited to browser-only mail or direct iOS installation.
Verdict
SpamSieve fits users whose mail program appears on its supported Mac list and who want local processing with customizable rules. Confirm client compatibility and the one-time $39.99 starting price before purchase.
Plans and prices
From SpamSieve's own pricing page, checked 8 Oct 2026.
| Plan | Price | What it gives you |
|---|---|---|
| SpamSieve | $39.99, paid once | One person or one computer; family or 2 users: $63.98; volume discounts available · One-time purchase |
The facts
Each one read from SpamSieve's own pages, with the date it was checked.
What it does
- Contacts
- It integrates with the macOS Contacts app so messages from contacts are not marked as spam.checked 8 Oct 2026
- Custom rules
- Users can create allowlist and blocklist rules matching message headers or body text, including with regular expressions.checked 8 Oct 2026
- Email accounts
- It works with any mail provider or host, filters all mail accounts, and charges no extra fee for additional addresses or devices.checked 8 Oct 2026
- Filtering
- It uses Bayesian spam filtering that adapts to the mail you receive.checked 8 Oct 2026
- iPhone and iPad
- SpamSieve does not run on iOS, but a Mac running SpamSieve can filter mail that synchronizes to an iPhone or iPad using IMAP or Exchange.checked 8 Oct 2026
- Mail integrations
- Supported current Mac mail programs include Apple Mail, Airmail, GyazMail, MailMate, MailMaven, and Outlook.checked 8 Oct 2026
- Message inspection
- SpamSieve can decode encoded messages and inspect attachments for spam content.checked 8 Oct 2026
- Privacy
- Mail data stays on the Mac; SpamSieve does not need mail account login access and does not transmit mail data elsewhere.checked 8 Oct 2026
- Purchase and upgrades
- The app is sold as a one-time purchase; maintenance releases and minor feature updates are free, while major upgrades may be discounted depending on purchase date.checked 8 Oct 2026
- Purpose
- SpamSieve adds spam filtering to an e-mail client on a Mac.checked 8 Oct 2026
- Requirements
- SpamSieve works with macOS 10.13 and later and requires a compatible Mac mail program.checked 8 Oct 2026
- Support
- The maker offers individualized support by email and provides a user forum, manual, and mailing list.checked 8 Oct 2026
- Unsupported clients
- Outlook Live and other browser-based mail are unsupported except through the listed Mac clients.checked 8 Oct 2026
The company
- Maker
- C-Command Software was founded in January 2002 by Michael Tsai to develop Mac utilities and productivity applications.checked 8 Oct 2026
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