Gmail contacts-only filtering
Gmail only allow emails from contacts: the practical way to do it.
Gmail filters can match senders, words, and labels, but Gmail does not expose one native contacts-only switch. KeepKnown uses Google Contacts as the allow-list and moves everyone else out of the inbox without deleting mail.
Gmail's filter workflow lets you enter search criteria and choose actions such as archive, label, delete, star, and forward. That is useful for known patterns, but it does not include a native condition for every sender who is not already in Google Contacts.
KeepKnown fills that gap by treating Google Contacts as the allow-list. Known people stay visible. Non-contact senders move to the recoverable KK:OUTSIDERS label, so you can review unfamiliar senders without letting them own the inbox.
Sources: Google Gmail filter help and Google Gmail search operators help.
Short answer
Gmail does not have a native contacts-only inbox setting.
Use Gmail filters for exact rules. Use KeepKnown when the rule is: only people in Google Contacts should stay in the inbox.
How contacts-only Gmail screening works.
Contacts pass through
KeepKnown checks whether the sender is already in Google Contacts before deciding where the message belongs.
Outsiders are recoverable
Messages from non-contact senders move to KK:OUTSIDERS instead of being deleted or permanently blocked.
No body reading
Routing is based on sender relationship, not scanning message body text to guess importance.
When this beats a native Gmail filter.
Public founder inboxes
Cold outreach and vendor pitches stop competing with known contacts.
Executive Gmail accounts
New senders go to a review lane until they earn contact status.
Privacy-sensitive users
The rule is deterministic and contact-based, not AI body analysis.
Questions before you connect.
Can Gmail only allow emails from contacts?
Not with one native contacts-only setting. Gmail filters can match search criteria, but Gmail does not expose a built-in rule for every sender who is not in Google Contacts.
Can I block Gmail emails that are not in contacts?
You can build manual filters for known patterns, but a strict contact-list gate needs another layer. KeepKnown screens non-contact senders into a recoverable label instead of deleting them.
Will KeepKnown delete email from people not in contacts?
No. Outsider messages move to KK:OUTSIDERS and remain recoverable. Add a sender to contacts when future messages should pass through.
Does KeepKnown read Gmail message bodies?
No. The contacts-only routing decision uses sender metadata and contact membership, not message body text.
Related inbox workflows
Contacts-only Gmail
Count how many non-contact senders are reaching your inbox.