LineLayer
Contacts-based filtering
LineLayer applies this exact rule: filter visible numbers that aren't in your contacts, so your phone rings mainly for people you've saved.
Android call blocking
Block All Calls Except Contacts on Android
If you want your phone to ring only for people you've saved, the rule is simple to state and inconsistent to actually find on Android: allow calls from numbers already in your contacts, and filter visible numbers that aren't. LineLayer applies that rule directly, with allow and block lists for the exceptions you need.
Why this is harder to set up than it sounds
Android doesn't offer one universal contacts-only switch across every phone. Some Samsung
Galaxy phones offer a more direct non-contact option, while Phone by Google's Unknown
setting blocks private or unidentified numbers rather than every visible number outside
your contacts. A rule-based call-filtering app like LineLayer can enforce contacts-based
filtering directly.
Availability varies by carrier and model. For the exact menu paths on Google, Samsung, and Pixel, see our full guide to blocking calls not in your contacts on Android.
"Unknown," "private," "hidden," and "not in contacts" also don't all mean the same thing, even though people often use them interchangeably. See private, hidden and unknown calls and how "unknown" is defined differently across Android phones for the full breakdown.
What "contacts-only" actually means as a rule
This is an allow-list rule, described from either direction: allow visible numbers already saved in your contacts, and filter everything else. A visible number saved in your contacts can reach you. A visible number that isn't saved doesn't, unless you've explicitly allowed it.
Allow and block lists handle the exceptions: numbers you always want through, and numbers you never want to hear from, independent of whether they're saved contacts.
How LineLayer fits
Allow and block lists
Keep a list of numbers you always want through, and a separate list you never want to hear from — independent of whether they're saved contacts.
Expected Call Mode
Temporarily relax the rule while you're waiting for a legitimate call from a number you don't recognize, like a callback from a clinic or a delivery driver. Your normal rule applies again once it's off.
Explainable history
Every filtered call is logged with the reason it was allowed or blocked, so the rule stays visible instead of feeling like a black box.
Local-first decision-making
Contacts-based rules are evaluated on your device, using rules you set. LineLayer can also check public reported activity for a number, and Smart Protection, part of LineLayer Pro, can automatically handle calls with strong reported-activity matches.
What this rule doesn't cover
A contacts-only rule only evaluates visible numbers Android makes eligible for call screening. Calls whose presentation is private, hidden, unidentified, unavailable, or from a payphone aren't included, so this can't guarantee blocking every private or hidden call — and that behavior varies by Android version, phone manufacturer and carrier.
Blocking everyone except your contacts also blocks legitimate first-time callers: clinics, delivery drivers, recruiters, banks, and similar calls from numbers you haven't saved yet. Pair the rule with an allow list for numbers you know you'll want, or a temporary exception like Expected Call Mode for calls you're specifically expecting.
What this means for your contacts
Applying a contacts-based rule requires checking an incoming number against your saved contacts, which is why LineLayer can request Contacts permission. That check happens on your device — LineLayer doesn't upload your contacts to apply this rule. See Android call blocking without uploading your contacts for the full explanation of how that works and what it doesn't do.
Questions before you install
Can Android block all calls except contacts?
Not with one universal switch. Phone by Google's Unknown setting doesn't do this — it targets private or unidentified numbers, not every visible number outside your contacts. Some Samsung Galaxy phones offer a closer option. A call-screening app like LineLayer can apply the rule directly, evaluated against calls Android makes eligible for screening.
"Block unknown callers" — does that mean block non-contacts?
Not necessarily. On Phone by Google, Unknown blocks private or unidentified numbers, not every visible number outside your contacts. The terminology varies by phone and manufacturer.
Can LineLayer block private or hidden calls?
Not universally. Android doesn't pass calls with private, hidden, unidentified, unavailable or payphone presentation to the call-screening system LineLayer uses, so it can't guarantee blocking every one of those calls.
What if I'm waiting for a delivery, clinic, bank, or recruiter call?
Use Expected Call Mode to temporarily relax the rule for a legitimate unfamiliar call you're expecting, or add the number to your allow list once you know it.
Does LineLayer upload my contacts?
No. LineLayer checks an incoming number against your saved contacts on your device. Your contacts aren't uploaded anywhere.