Guides
Practical, privacy-first guides to blocking spam and unknown callers on Android.
Getting started
How to Block Unknown & Spam Callers on Android
Step-by-step guide to block or silence spam and unknown callers on Android — any number not in your contacts. No sign-up, no contacts access, 100% on-device. Free.
How to Stop Robocalls & Scam Calls on Android
A practical guide to stopping robocalls, spam, and scam calls on Android. Block every number not in your contacts — no sign-up, no contacts access, 100% on-device. Free.
How to Silence Unknown Callers on Android
Silence unknown callers on Android — mute the ringer for any number not in your contacts while still keeping the call in your log. No sign-up, no contacts access, free.
What Is Call Screening on Android?
Call screening on Android explained: what the call-screening role does, how an app filters unknown calls without your contacts, and why it's safe and private.
How to Block Calls Not in Contacts on Samsung Galaxy
Block calls from numbers not saved in your contacts on a Samsung Galaxy. Compare Samsung's built-in settings, Smart Call, and a private Android call blocker.
Why Do Blocked Calls Go to Voicemail on Android?
Learn why a blocked Android call may still reach voicemail, how Phone apps and carriers differ, and what Block versus Silence mode actually changes.
How to Block Spam Without Missing Important Calls
Stop spam calls without missing deliveries, hospitals, banks, interviews, or emergencies. Use allow lists, repeat calls, pause, and Silence mode on Android.
Call Blocker Not Working on Android? 8 Things to Check
Fix an Android call blocker that is not blocking calls. Check the call-screening role, mode, pause, allow list, repeat calls, contacts, scope, and voicemail.
What Happens When You Block a Number on Android?
Find out what a blocked caller experiences on Android, whether they are notified, what happens to voicemail and call history, and how blocking differs by app.
By country
How to Stop Spam Calls in India
Stop spam and scam calls in India. Why TRAI DND isn't enough, and how to block every number not in your contacts on Android — no sign-up, no contacts access, free.
How to Stop Spam Calls & Robocalls in the USA
Stop robocalls and spam calls in the US. Why the Do Not Call Registry and STIR/SHAKEN aren't enough, and how to block every number not in your contacts on Android — free.
How to Stop Spam Calls in Brazil
Stop spam and telemarketing calls in Brazil. Why Não Perturbe and the 0303 prefix aren't enough, and how to block every number not in your contacts on Android — free.
How to Stop Spam Calls in Mexico
Stop spam and telemarketing calls in Mexico. Why the REPEP registry isn't enough, and how to block every number not in your contacts on Android — no sign-up, no contacts access, free.
Compare & alternatives
A Private Truecaller Alternative for Android
Looking for a Truecaller alternative that doesn't upload your contacts or need an account? Block Unknown Callers blocks every number not in your contacts — 100% on-device, free, no sign-up.
Best Free Call Blocker Apps for Android in 2026
Compare 10 Android call blocker apps by privacy, blocking method, free access, caller ID, and setup. See our transparent ranking and the best app for each need.
Google Call Screen vs. a Call Blocker
Google Call Screen and Android call blockers solve different problems. Learn when to use Pixel Call Screen, caller ID spam protection, and privacy-first blocking.
Block Unknown Numbers vs. Block Calls Not in Your Contacts
Why blocking 'unknown numbers' on Android doesn't stop your spam. The difference between blocking unknown (hidden caller ID) numbers and blocking every number not in your contacts.
A Truecaller Alternative for India
A private Truecaller alternative for India: block spam and unknown callers on Android without an account or contacts upload. Free, on-device, no sign-up.
Scams & safety
How to Block International Spam Calls on Android
Stop international spam and 'one ring' (wangiri) scam calls on Android — block by country-code prefix or filter every foreign number, without an account or contacts access. Free.
What Happens If You Call Back a Spam Number?
Calling back a spam or one-ring (wangiri) number can cost you money and confirm your number is active. Here's what happens, the warning signs, and how to avoid it.
Is It Safe to Answer Calls from Unknown Numbers?
Is it safe to answer unknown calls? The real risks (active-number confirmation, AI voice scams, pressure tactics), when it might be genuine, and a safer way to handle them.
How Do Scammers Get Your Phone Number?
How scammers and spammers get your phone number — data breaches, data brokers, public posts, random dialing, contact-uploading apps — and how to reduce exposure and block them.
Neighbor Spoofing Explained
Neighbor spoofing makes spam calls look like nearby numbers with your area code or prefix. Learn why it works and how to stop local-looking unknown calls on Android.
STIR/SHAKEN Explained
STIR/SHAKEN helps phone companies authenticate caller ID, but it does not block every spam call. Learn what it does and how Android users can stop unknown callers.
How to Protect Seniors from Scam Calls on Android
Set up layered Android protection for an older parent or family member: trusted contacts, spam filtering, unknown-call blocking, exceptions, and scam safety rules.