KeepKnown: Free Gmail Stranger Audit

KeepKnown is the allow-list email filter for Gmail, Google Workspace, Outlook, and Microsoft 365. Only people in your contact list reach your inbox. Everyone else is automatically labeled and archived in a recoverable review area — not deleted, never lost. --- THE PROBLEM KEEPKNOWN SOLVES Gmail and Outlook are powerful, but neither offers one simple rule: only let emails from my contacts through. Gmail filters can match senders, keywords, subjects, categories, and labels. Outlook rules and safe senders lists handle known addresses and domains. Neither platform offers a native "sender not in contacts" condition that covers every unknown sender automatically. That gap is where KeepKnown lives. Public email addresses attract cold outreach, vendor pitches, recruiter sprays, sales sequences, webinar invites, and unsolicited partnerships. All of it passes spam filtering because it is technically legitimate. All of it competes with emails from your board, your team, your customers, and your actual relationships. Spam filters catch the illegal stuff. KeepKnown handles the legal stuff that should still not be in your inbox. --- HOW IT WORKS KeepKnown connects to Gmail, Google Workspace, Outlook, or Microsoft 365 and uses your existing contact list as the allow-list. When a new email arrives, KeepKnown checks whether the sender is already in your contacts. If they are, the email stays in your inbox exactly as normal. If they are not, the email is automatically labeled and moved to KK:OUTSIDERS — a dedicated review area you can check when it suits you. Nothing is deleted. Nothing is permanently blocked. When you add someone to your contacts — a new client, a new hire, a journalist you just spoke with — KeepKnown syncs automatically and that person's future emails come straight through. No rules to update, no filters to rebuild. --- WHAT KEEPKNOWN IS NOT KeepKnown is not a spam filter. Spam filters use pattern detection, sender reputation, and machine learning to catch unsolicited bulk mail and phishing. That work still happens. KeepKnown operates on top of it. KeepKnown is not an AI email summarizer. It does not read your email bodies to decide what is important. The routing decision is based entirely on one question: is this sender in your contacts? Nothing else. KeepKnown is not a blocklist. It does not permanently reject or bounce emails. Outsiders land in KK:OUTSIDERS, not in a void. A new customer who emails for the first time, a journalist writing a profile, a recruiter with a genuinely interesting role — all of them can be found in the review area. Add them to contacts and they come through normally from that point forward. --- GMAIL FEATURES Gmail filter sender not in contacts — the condition Gmail does not expose natively. KeepKnown adds automatic routing for every sender outside Google Contacts without manual filter rules. Gmail only allow emails from contacts — Gmail has no native contacts-only inbox mode. KeepKnown uses Google Contacts as the allow-list so known senders stay in the inbox and everyone else moves to a recoverable review lane. Gmail unknown sender filter — instead of building dozens of individual Gmail filters for specific cold senders, one KeepKnown connection handles all unknown senders at once. Gmail contact-based screening — routing is based on your actual relationships, not AI body analysis or importance guessing. Gmail filter unknown senders automatically — real-time, 24/7, background filtering with no manual steps. Every new email is checked the moment it arrives. Gmail allow-list filter — your Google Contacts become the live allow-list. As your contacts grow, the list expands automatically. Gmail not in contacts rule — create the inbox behavior Gmail should have built in. Contacts in. Strangers out. Recoverable, always. KK:OUTSIDERS label — a dedicated Gmail label where non-contact senders land. Searchable, filterable, and one click from your inbox when you want to review. Apply to existing emails — optionally run KeepKnown on mail already in your inbox to retroactively move outsider mail to the review area. Google Workspace support — KeepKnown works with personal Gmail accounts and Google Workspace business accounts. --- OUTLOOK AND MICROSOFT 365 FEATURES Outlook whitelist-only mode — Outlook safe senders and Microsoft 365 mail flow rules handle known addresses well. KeepKnown adds the relationship layer: approved contacts stay visible, everyone else moves to a recoverable review area. Outlook approved senders only — executives, founders, and security-sensitive Microsoft 365 teams can set a stricter default without permanently blocking any sender. Microsoft 365 contact-based inbox — connect your Outlook account and KeepKnown treats your Outlook contacts as the allow-list, routing non-contact senders away from your main inbox. Outlook filter unknown senders — cover the gap that native Outlook rules leave open: the open-ended stream of cold outreach that is not spam but also should not interrupt the inbox. Outlook sender not in contacts — the same contact-based logic that Gmail users get, applied to your Outlook or Microsoft 365 inbox. Microsoft 365 inbox allow-list — for organizations that want stricter sender control without complex admin policies or third-party mail flow changes. --- PRIVACY AND SECURITY Google CASA Tier 2 verified. KeepKnown has passed Google's Cloud Application Security Assessment at Tier 2, which requires independent security testing by a certified lab. Most extensions skip this entirely. OAuth verified by Google. The Google OAuth application review process requires demonstrating that permission scopes are used appropriately and that user data is handled responsibly. We never read your emails. KeepKnown only checks the sender's email address against your contacts. It does not access, scan, parse, or store email subject lines or email body content for any purpose. Contacts are never stored as plaintext. …