The best free spam-call blocker app for iPhone

Are you receiving so many spam calls and texts to your iPhone that you’re considering downloading an app to block unwanted calls? There are plenty of free apps on the App Store that promise just that. But before you rush to download one—they may actually increase the volume of spam you receive if they share your personal information (which, it turns out, many of them do).

We came up with a list of only four spam-blocking apps that passed our minimum privacy requirements.

Mariam Volobueva

NOTE: If you’re receiving a lot of spam, your personal information—like your phone number—may be for sale on data broker sites.

1) T-Mobile Scam Shield

App Store rating

4.7/5

Features

• Scam block: Automatically blocks calls from numbers that likely belong to scammers.
• Scam reporting: Allows you to report numbers that may belong to spammers (or scammers), adding them to your personal spam list.
• Caller ID: Lets you see who’s calling before you answer.
• Allow list: Lets you save numbers you want to receive calls from that would otherwise be blocked.

Data privacy

T-Mobile has a very detailed privacy policy that we recommend you check out for yourself before downloading the Scam Shield app. It lists the different types of data they process, along with their use cases. 

Data they process that is directly linked to you:

• Name
• Email address
• User content
• Product interactions
• Customer support interactions.

Data they process that is not directly linked to you:

• Phone number
• Search history
• Device ID
• Crash data.

While they claim not to “sell” data, they do admit to sharing it, primarily to provide services. Third parties they share data with for this purpose include data analytics providers, internet service providers, operating systems and platforms, and payment processors and financial institutions. 

However, they also share data for marketing purposes to advertising networks and social networks. 

2) YouMail

App Store rating

4.7/5

Features

• Spam and robocall blocking: Automatically blocks spam calls and robocalls.
• Personal block list: Allows you to create a personal spam list of numbers you want to block.
• Call handling: Helps you manage your voicemail with features including voicemail to text and email, personalized voicemail greetings, and more.

Data privacy

YouMail claims to request permissions only when needed. However, its privacy policy states that it may share your information with third parties, including “service providers, business partners, advertisers, and other companies that are not affiliated with YouMail.” 

According to the App Store, all of the data YouMail states they process is linked directly to you. However, compared to some other spam-filtering apps, the scope of this data appears to be relatively limited. 

The data they process includes:

• Contacts
• User ID
• Customer support interactions
• Performance data
• Other diagnostic data
• Crash data.

3) AT&T ActiveArmor

App Store rating

4.4/5

Features

• Fraud-call blocking: Automatically blocks calls from numbers associated with fraudulent activity.
• Spam-call blocking: Automatically blocks spam-risk calls or sends them to voicemail, based on your preference.
• Nuisance-call alerts: Alerts you to telemarketing calls and other nuisance calls.
• Spam-call routing: Allows you to select which call categories you want to receive, block, or send to voicemail.
• Unknown calls to voicemail: Allows you to send all callers not saved in your contacts directly to voicemail.
• Block all texts from email: Allows you to block all texts originating from emails.
• Spam-text filtering: Filters texts from unknown senders or with malicious messages.
• Personal block list: Allows you to create a personal list of spam numbers you want to block automatically.
• Device security: Helps keep your iPhone secure.
• Breach reports: Sends you alerts about the latest company data breaches.

Data privacy

While most of it isn’t directly linked to you, AT&T collects quite a bit of your data. Beyond what they disclose in the App Store, AT&T’s privacy policy reveals that they collect more information than may appear at first glance. This includes location data, biometric info such as fingerprints and voice scans, and information they collect from third parties (likely data brokers). 

They also share information with affiliates and third-party advertisers and service providers. While they may not share some of the most sensitive information (such as fingerprints, passwords, or personal texts), simply having this data is risky enough.

In April 2024, AT&T experienced a massive data leak affecting millions of users. The information leaked was so sensitive that the FBI had concerns about its potential impact on public safety and national security.

Data ActiveArmor collects that’s linked to you:

• Phone number
• Contacts.

Data ActiveArmor collects that isn’t linked to you:

• Name
• Photos and videos
• Email address
• Browsing history
• Product interactions
• Device ID
• Crash data
• Performance data
• Other diagnostic data
• Other user content.

4) Verizon Call Filter

App Store rating

4.5/5

Features

Call Filter features include:

• Spam alerts: Sends alerts regarding suspected spam callers with associated risk levels.
• Spam blocking: Automatically sends high-risk spam calls to voicemail.
• Spam reporting: Allows you to report suspicious calls.
• Filters: Lets you select the types of calls, such as robocalls, you want to automatically block.

Data privacy

Verizon’s privacy policy raises a few red flags for us, putting it lower on our list. If you’re already a Verizon customer, using their app shouldn’t make much of a difference to your privacy; if you aren’t, we don’t recommend it. 

Their privacy policy states that they allow third-party advertisers to collect your information from the app, potentially combine it with data collected from other sources (potentially from data brokers), and use that data to serve ads. The privacy policy becomes more vague when it comes to who is allowed to use that data. They state that advertisers, including Verizon, may use the information to serve targeted advertising, implying that they may be spreading your data among other companies too. 

They also state that they may “publish your name, address and wireline telephone number(s) or provide this information to directory publishers, assistance services, or others. These companies can use this information in other formats or for other purposes, and they may make it available to others.”

Most of the information they collect, based on the information provided in the App Store, is directly linked to you. 

This includes:

• Name
• Phone number
• Contacts
• User content
• Usage data
• Crash data.

The only information they say is not linked to you is product-interaction data.

How to pick the best app to block spam calls on an iPhone

There are several things to consider before downloading a spam-filtering app on your iPhone. All of them are important, but the weight of each metric can vary from one person to the next. We placed the most value on data privacy as this can not only put your security at risk in case of a data leak, but it also exacerbates the issue at hand: spam. 

The App Store rating gives you a general idea of how effective the app actually is at blocking unwanted calls. If the app is popular (meaning it has many downloads) and maintains a high rating, it’s a good indicator that the app does what it promises. 

While some of you may be looking for only the most basic spam-blocking features, some apps might provide additional services you may find useful. You should compare the features carefully to get the most bang out of your 0 bucks (and data). 

Pay attention to how apps handle your data. If they collect and share few data points, they should be relatively safe. Apps that collect more data points but share few of them still pose risks as data breaches are a growing threat. Apps that collect and share a lot of data represent a higher risk. Worst of all are apps with ties to data brokers, as they directly contribute to the problem they then provide a solution to. It can be hard to identify these connections, but a good indicator that a spam-blocking app may have ties with a data broker is if it also provides a “reverse phone lookup” service. 

To sum up, the best spam-blocking app for your iPhone is one with a high rating that provides features that address your needs and collects and shares as little information as possible.

So, should you block unwanted calls using an app?

The short answer is no. Because of the risks involved, we don’t recommend using spam-blocking and call-filtering apps.

Even when an app is from a trusted developer, the chances of a data breach, such as the one AT&T experienced in April 2024, are never zero. It’s also important to note that all of these apps are proprietary software, meaning that while they may claim to handle your data with discretion, we have very limited ways of checking for ourselves. 

Not to mention that, by nature, spam-blocking apps require access to TONS of your personal information, including your:

• Name
• Phone number
• Email
• Contacts
• Call logs
• Voicemail
• Text messages
• Photos, videos, and audio.

Most (if not all) spam-blocking apps also share your data for advertising purposes. They may reduce spam calls and texts to your iPhone but they may also cause an increase in spam to your email, online messaging apps, social media, and physical mailbox—not to mention targeted online ads. And naturally, the more places your information lives, the greater your chances of data breaches, scams, identity theft—and increased spam. 

How to block all spam on your iPhone

If our warnings have scared you off downloading a spam-blocking app, fear not. There are other ways to prevent spam from flooding your iPhone. These methods may take longer, but don’t expose you to increased spam and security threats to everything else outside of your phone.