Telemarketing calls and calls from unknown numbers are exhausting for anyone. The good news is that there's a series of steps that solves a large part of the problem—and the first one is free, official, and doesn't require any installation.
This guide begins with what the phone itself already does, goes through the official blocking registration in Brazil, and only then gets to the applications, all checked in the... Play Store. It also explains what to look for in the permissions before installing any of them.
1. Start by removing the phone's native lock screen.
Both Android and iPhone block numbers without an extra app. On Android, open your call history, tap the number, and choose to block and report it as spam. On iPhone, it's the information button next to the call, followed by "Block this caller".
Both systems also have the option to silence calls from unknown numbers: they go directly to voicemail and appear in the call history without ringing. It's the most effective measure for those who receive many business calls — and it costs nothing.
2. Sign up for Do Not Disturb
It is the official platform maintained by telecommunications operators under the supervision of Anatel, at the address donotdisturb.com.br. Registration is free and blocks telemarketing calls from participating companies — telephone operators, banks and financial institutions.
The block takes effect up to 30 days after registration. Several states also have their own registration systems through Procon (consumer protection agency), which expand the list of covered sectors. It's worth registering both.
It's important to know the limit: registration only applies to companies that have joined the system. Calls from scammers don't respect any registration—for these, caller ID and manual blocking are sufficient.
3. Use Google Caller ID.
The application Google Phone, With a 4.5 rating and over 50 million reviews, it comes pre-installed on a large number of Android devices and includes caller ID and spam protection.
In the settings, enable "Caller ID and spam" and, if you want, automatic screening. It's the most discreet option in terms of privacy because it doesn't rely on sending your entire contact list to a third-party server. View on the Play Store.
Specialized applications
Truecaller
The best-known in its category: rated 4.5 and with over 29 million reviews. Identifies callers from a massive collaborative database and automatically blocks numbers marked as spam.
It's important to understand how this database is built: historically, the service model involves access to users' contact lists. In other words, your contacts' numbers can populate the database. Whether this is acceptable or not is your decision, and it's information that should be provided before installation, not after. View on the Play Store.
Whoscall
Rated 4.1 and with over 800,000 reviews. It identifies calls in real time, allows you to look up numbers, and has an offline database that works without consuming internet data per call.
It also provides warnings about known scams, which helps with calls impersonating banks. View on the Play Store.
Hiya
Rated 4.3 and with approximately 262,000 reviews. Identifies and blocks unwanted calls, with a simple interface and no excessive features. Performs reverse phone number lookup.
It's a more streamlined alternative to Truecaller, with similar functionality. View on the Play Store.
Mr. Number
Rated 4.6 and with around 200,000 reviews, from the same developer as Hiya. Its distinguishing feature is range-based blocking: it allows you to block all numbers within a specific area code or a particular prefix.
Useful when the discomfort always comes from the same area. View on the Play Store.
Call blocking — Dialer
Rated 4.5 and with approximately 45,000 reviews. Lightweight and straightforward app, focused on blocklists: specific numbers, unknown numbers, and area codes. It doesn't require a collaborative user base or broad data access.
It's the simplest option for those who just want to block calls, without caller ID. View on the Play Store.
What no app does
None block all Unwanted calls. Scammers constantly change their numbers and use fake numbers that mimic your city's area code—when a new number appears, no database recognizes it yet.
None of them reveal the personal data of the line holder. Any app that promises the name, address, or CPF (Brazilian tax ID) of the caller is inventing or processing personal data without a legal basis, which violates the General Data Protection Law. What legitimately exists is collaborative identification: people who marked that number as spam.
Be careful with permissions.
A blocking app needs access to calls and history — that's expected. Access to the complete contact list, on the other hand, is where it's worth pausing and thinking: it means handing over the numbers of everyone who trusted you with their contact information, and they weren't consulted.
Also be wary of requests for access to SMS, files, location, or camera in a call blocking app. None of that is necessary for the function. If an app requests permissions unrelated to its purpose, look for another one.
It's worth remembering that you can review permissions after installation, in Android Settings, in the applications section.
The recommended sequence
- Enable the silencing of unknown numbers in your phone's settings.
- Register with the "Do Not Disturb" service and the consumer protection agency (Procon) in your state.
- Turn on Google Phone's spam identifier.
- Only then, if it still bothers you, install a specialized app.
- Block and report every new number that comes through — it improves the database.
How does the "Do Not Disturb" service work, and what does it actually cover?
It's the most effective tool on the list and the least used, so it's worth detailing. It's a free, national registry maintained by the operators themselves as required by regulation, where you register your numbers to avoid receiving unwanted calls. telemarketing offer.
What needs to be clear:
- There is a deadline before it takes effect. The block is not immediate after registration.
- It covers commercial offers. Participating companies included: telecommunications, banks, financial institutions, and other sectors that were subsequently included.
- He doesn't charge you for debt collection., This includes contacting a company with which you have an active contract, conducting research, or calling a public service.
- He doesn't cover scammers. The caller pretending to be from the bank doesn't consult any list — and that's precisely the kind of call that's most important to recognize.
- It's worth recording all of your numbers., including fixed addresses, and check the registration after some time.
Non-compliance is subject to sanctions by the regulatory body, and complaints are filed through the registration channel itself — which gives some practical effect to the registration.
The coup that presents itself as a blockade.
A specific warning is in order, because this category is used as bait. There are calls and messages offering "registration for call blocking" that ask for personal data, a code received via SMS, or payment. The official registration is free and requires nothing more than your phone numbers.
Signs that the offer is fraudulent:
- Request for six-digit code Received via message — this code is used to take over your account, never for registration.
- Fee collection to “activate the block”.
- Shortened link in a message, instead of the official address you typed.
- Hurry "Your block expires today.".
- Request for bank details or password, under any justification.
Why does the identifier match the number but not the intent?
Apps that show who's calling work on a collaborative basis: people mark numbers as unwanted, and this feeds a database that is consulted with each call. It works well, with two important limitations:
- The new number is not in the database. Telemarketing and fraud operations constantly change numbers, and it's always the new number that gets passed around.
- False positives happen. A doctor's office, school, or work number may have been dialed in error—and the call you were expecting is blocked.
And the cost of this convenience deserves to be mentioned: Many of these apps request access to your entire calendar. and send it to the server. That's how the database grows — with the contacts of those who installed it. If that's not acceptable to you, the device's native lock, combined with the caller ID built into the system's dialer, resolves most cases without revealing anyone's contact list.
Conclusion
The most efficient approach combines what already exists on the phone, the official "Do Not Disturb" registration, and, if necessary, a specialized app. In that order, not the other way around.
And when choosing an app, look at the permissions before rating it. A blocker that requires your entire contact list to function is asking for more than it needs — and there are alternatives that do the same job without it.
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