How Xiaomi Recognizes Spam Calls: Technology, Databases, and Hidden MIUI Settings

Spam calls have become a scourge of modern times: according to Kaspersky, in 2023, one in three subscribers in Russia received fraudulent calls weekly. Xiaomi, Redmi and POCO smartphones based on MIUI use a comprehensive approach to block such calls, from global databases to machine learning. But how exactly does the system determine that a call is dangerous? Why do some numbers slip through the filter and others get blocked mistakenly?

In this article, we will take a closer look at the algorithms used to detect spam in MIUI firmware, including Xiaomi cloud databases, behavioral analysis, and the role of artificial intelligence. You will learn what data the system uses to make decisions, how to update databases manually, why legitimate numbers are sometimes blacklisted, and how to set up protection for your needs if standard mechanisms are not working effectively enough.

Cloud Databases: How Xiaomi Collects Spam Information

The foundation of spam-call protection at Xiaomi is centralized cloud databases that are updated in real time.

• 📊 User reports: When you flag a number as spam in the Phone app, the data is sent to Xiaomi servers and analyzed. If a single number is tagged by thousands of users, it automatically falls into a global blacklist.
• 🤝 Partner Services: The company works with anti-spam services like Truecaller (in some regions), Hiya and local carriers to share fraudulent number data.
• 🕵️ Traffic analysis: Algorithms track mass calls from a single number (e.g. 50)+ They block them proactively, even if users have not complained yet.

Interestingly, Xiaomi’s databases are segmented by region: a number blocked in India as spam may not be blacklisted in Russia unless local users complained about it, which explains why some fraudulent calls slip – especially from new schemes that have not yet had time to collect statistics.

It's important to understand that cloud databases are automatically updated, but sometimes forced synchronization is required, for example, after a major data leak, fraudsters en masse register new numbers, and fresh information can be delayed.

1. Open the phone app.
2. Go to Settings → Spam Calls → Update the database.
3. Wait until the process is completed (usually 5-10 seconds).

⚠️ Attention: if after updating the database spam calls continue to arrive, check whether the function "Block spam calls" in the settings of the application "Phone". MIUI It's off by default!

Local analysis: how a smartphone can detect spam without the Internet

Not all spam calls are blocked through the cloud, and Xiaomi uses local analysis mechanisms that work even without an internet connection.

• 🔢 Number patterns: Algorithms detect suspicious combinations, such as numbers with repeating numbers (+79991231231), short numbers (3-4 digits) or numbers with non-existent country codes.
• ⏱️ Call frequency: if your number is 3+ If you call from one number per hour, the system can block it as potential spam.
• 📞 Subscriber behavior: if the call is interrupted through 1-2 beeps (typical tactics of fraudsters to check the activity of the number), this increases the spam rating of the number.

Local analysis is less accurate than cloud-based analysis, but it works instantly and is independent of Internet speed, for example, if a fraudster uses a new number that has not yet reached the global databases, the smartphone may block it for behavioral signs.

MIUI 14+ has introduced Voice Message Analysis (includes in Phone Settings → Spam Calls → Additional Settings) which scans voice messages for fraudsters’ key phrases (e.g., “your card is locked,” “call back to this number”), which only works for messages left on the answering machine and requires permission to access the microphone.

The role of artificial intelligence in spam filtering

Since 2022, Xiaomi has been actively implementing machine learning to improve the accuracy of spam blocking.

• 📈 Interaction history: If you have previously received calls from similar numbers (e.g., from a bank), the system reduces the likelihood of blocking new numbers from the same network.
• 🗣️ Context of conversation: in models with Google Assistant or Xiao AI Analyze the content of conversations (with your permission) to detect fraudulent scenarios.
• 🌍 Geolocation: Calls from regions with high levels of spam (such as some African countries) get more rigorous screening.

AI also takes into account the time of day: calls at non-working hours (such as 3 a.m.) automatically receive a higher “spam rating,” but this mechanism can give false positives if you are actually being called from another time zone.

Xiaomi 13/14 and its flagship Redmi models use a neural network to analyze voice, which compares a caller’s voice to databases of known scammers and can block a call before you even pick up the phone, a feature that only works on Chinese and global firmware with support for Xiao AI.

Why legitimate numbers get spammy and how to fix it

Sometimes the system mistakenly blocks real calls, such as from banks, delivery services or colleagues, for several reasons:

• 🔄 Database conflict: a number may have been labeled as spam by other users by mistake (for example, if it previously belonged to a fraudster).
• 📱 Aggressive settings: in some firmware MIUI Spam filtering level is set to default maximum.
• 🌐 Regional features: numbers with the code of another country (for example, +375 for Belarus) may be automatically considered suspicious.

To exclude the number from spam:

Open the call log in the "Phone" application"|Find the blocked number and click on it.|Select "Delete from spam" or "Unblock"|Check that the number is added to the contacts (this will reduce the risk of re-blocking)-->

If the problem recurs, try resetting the spam filter settings:

1. Go to Settings → Applications → Application Management → Phone.
2. Select Warehouse → Clear the data (this won’t delete your call history, just your filter settings).
3. Reboot your smartphone.

⚠️ Warning: After resetting the spam filter, you will have to re-update your cloud databases and adjust the lock level, which in some cases helps to eliminate the “stuck” errors in the local cache.

Hidden MIUI settings for fine-tuning spam blocking

There are hidden parameters in MIUI firmware that allow you to more flexibly configure call filtering to access them:

1. Open the phone app.
2. Enter the code in the search box (loop at the top): ##4636##.
3. Select Phone Information → Spam settings (on some models, the path may be different).

Here you will find additional options:

• 🔍 Filter sensitivity: You can select the level from “Low” (only obvious spam calls are blocked) to “Aggressive” (all suspicious numbers are blocked).
• 📡 Background Base Update: Turn on this option to update databases automatically without your involvement.
• 📵 Hidden Number Blocking: Automatically cuts off calls with a suppressed ID (e.g., “Unknown Number»).

Xiaomi’s HyperOS models (starting in 2026) have introduced Smart Lock, which adapts to your habits, for example, if you frequently receive calls from unknown numbers during business hours, the system will reduce filtering levels during these hours.

💡

If you get frequent calls from abroad, add the prefixes of those countries to the whitelist through Phone Settings → Spam Calls → Whitelist.

How fraudsters bypass Xiaomi’s defenses and how to counter it

Spammers are constantly adapting to new blocking methods, and here are the current schemes for circumventing protection in 2026 and ways to counteract:

One of the most dangerous trends of 2026 is calling from numbers similar to your contacts. For example, a scammer may call from a number that differs from yours by only one digit (+79123456789 instead of +79123456788) In this case, only care helps: always check the number before answering.

If you are a victim of such fraud, report the number to Xiaomi:

1. Open the call log.
2. Find a suspicious number and click on “Complain”.
3. Select the Fraud category and add a comment (this will help improve the algorithms).

💡

Never return calls to unknown numbers, even if the answering machine has a message about "card lock" or "delivery problems." Fraudsters often use such tricks to get you to call them back to a paid number.

FAQ: Frequent questions about blocking spam calls on Xiaomi