Your Rules, Your Machine.
A fast, local-first spam filter for Outlook, Apple Mail, and Thunderbird. Free for personal use, and your email never leaves your computer.
Windows & macOS • Free For Personal Use
One local hub, every inbox. Thin add-ins in your mail apps feed a single filter running locally on your computer.
Notice a spam email in your mail app, just like any normal day.
One click instantly builds a local rule blocking the sender domain and signatures.
SpamBlaster automatically sweeps matching junk off your machine.
SpamBlaster is engineered so your email remains 100% private.
Everything runs directly on your computer (127.0.0.1). No external servers access your mail.
Your block rules live inside an encrypted local database secured by your operating system.
Mailbox access tokens live exclusively in Windows Credential Manager or macOS Keychain.
Block logs save rule patterns only. Never message subjects, bodies, or attachments.
No analytics, no background tracking, no cloud pings. Your email stays 100% private.
Read the full Privacy Policy.
Mailboxes: Microsoft 365, Gmail, IMAP. Windows & macOS.
Select a spam message, click Blast, and watch it go. Review every rule and every blocked message in the dashboard across all your mail apps.
Everything you need to know about SpamBlaster local spam filtering.
SpamBlaster is free for individuals. If it keeps your inbox clean and you want to help it grow, you can chip in.
Sponsor on GitHub