How to Set Up a Contact Only Email Filter
Route non-contacts out of your Inbox in ~10 minutes using Gmail filters, labels, and precise “from:” rules.
Aymane S.
Everything you need.
Nothing you don't.
24/7 Vigilance
Real-time monitoring keeps your inbox clean round-the-clock. Every email is instantly checked against your contacts.
Auto Sync
Never miss newly added contacts. Everything syncs automatically from your email provider.
Custom Filters
Manage allow-lists and domain filtering for complete inbox control.
Privacy First
Contacts are hashed for matching and encrypted for debugging. Never stored as plaintext. We never sell or share your data.
Join thousands simplifying their inbox.
0+
emails filtered and counting
Loved by professionals
See how KeepKnown helps people reclaim their inbox.
"KeepKnown has completely changed how we manage our inbox. We used to waste so much time sorting through junk mail — now it's clean, efficient, and stress-free. The spam control is spot-on, and we finally feel in control of our email again."
From the blog
Tips, insights, and updates on mastering your inbox.
Aymane S.
Unsubscribe Not Working: Methods Compared That Actually Scale
When unsubscribe fails, you’re stuck in a loop of junk, risk, and lost time. Here’s why strict allowlisting wins architecturally.
Aymane S.
How to Enable Outlook Whitelist Only Mode
Make Outlook deliver only approved senders to your Inbox. Setup takes ~7–15 minutes, plus up to 48 hours for changes to fully apply.
Aymane S.
Frequently Asked Questions
Everything you need to know about privacy, security, and how KeepKnown works.
No, we never read your emails. KeepKnown only checks the sender's email address against your contacts list. We don't access, store, or analyze the content of your emails. Your email content remains completely private.
No, your contacts are never stored as plaintext. We store a per-user one-way lookup token (HMAC-SHA256) for matching. For the debugger, we may also store an encrypted copy so you can view the actual address.
Absolutely not. Your information is never shared with, sold to, or used by any third party. Our business model is simple: you pay for the service, and that's it. We don't monetize your data.
Yes. KeepKnown has passed Google's security assessment (CASA Tier 2) and OAuth verification. Google has reviewed our app, verified our identity, and confirmed we handle your data securely.
Yes, always. We never delete emails - they're simply labeled and archived. Click the "KK:OUTSIDERS" label in your email client to see all filtered emails and move any back to your inbox with one click.
Still have questions? Contact our support team
Simple, transparent pricing
Choose the plan that fits your workflow. Start with a 7-day free trial.
Starter
Perfect for personal use
$
29
23
/ month
Billed annually ($276/year)
Or save 20% with yearly billing
- 1 email account connected
- Gmail, Outlook & Microsoft 365
- Unlimited email filtering
- Real-time contact sync
- Custom allow-lists
Most Popular
Pro
For power users & small teams
$
60
48
/ month
Billed annually ($576/year)
Or save 20% with yearly billing
- 3 email accounts connected
- Gmail, Outlook & Microsoft 365
- Unlimited email filtering
- Real-time contact sync
- Priority support
- Advanced analytics dashboard
Agency
For teams & organizations
Custom
Tailored to your needs
- Unlimited accounts
- Team management console
- Dedicated account manager
- Custom integrations
- SLA & uptime guarantee
- Onboarding & training
7-day free trial
No credit card required
Cancel anytime