Application installation files APK are often perceived by users as a “black box”: we download them, run the installation, but rarely think about what exactly is inside. However, a situation when it is necessary to look “under the hood” of a app arises quite often. For example, if you want to check the authenticity of an application, find hidden resources, or simply understand why a file is not installed on your device.
Unlike computer files that require emulators to run on mobile OSes, the APK format is an archive whose structure can be analyzed even without installation. EXE files that require emulators to run on mobile operating systems, the APK format is an archive whose structure can be analyzed even without installation. APK is a ZIP archive, renamed to the .apk extension, containing Dalvik code, resources and a manifest. This means that you can access it using standard operating system methods to most components, if you know the right approach.
In this guide, we will look at all the current ways to view the contents of such files. We will look at both simple methods for ordinary users, and more advanced tools for those interested in the technical side of the issue. It is important to understand that working with executable files requires caution, as malicious code may be hidden inside.
Standard browsing through a file manager
The fastest and most accessible way to see what is inside the installation package does not require installing additional software. Modern file managers, such as Files by Google, MIUI File Manager or Solid Explorer, can work with archives. Since an APK is essentially a renamed ZIP, the system often allows you to open it as a regular archive.
To do this, just find the file in the device’s memory and click on it. If the file manager supports working with archives, it will offer to open the contents. You will see folders assets, res, lib and file AndroidManifest.xml. However, it is worth considering that standard viewers will not be able to decode binary resource files or show readable code, since they display “raw” data.
This method is suitable for quickly checking for the presence of suspicious libraries or confirming the size of embedded data. If you see a strange package name inside or lack of a standard folder structure, this may indicate a modified application.
- 📁 Open a file manager and go to your downloads folder.
- 📁 Click on the APK file and select the "Open as archive" or "Extract" option.
- 📁 Explore folder structure to check data integrity.
If the file manager does not open the file, try renaming the extension from .apk to .zip directly in Explorer, this often helps standard archivers recognize the structure.
Specialized APK analyzers for Android
For deeper analysis that goes beyond simple viewing folders, it is better to use specialized tools. Applications like APK Analyzer or Package Inspector allow you to see detailed information about the application even before installing it. Such apps read the manifest and show the requested permissions, the libraries used and the target version of Android.
Using an analyzer gives an understanding of which system components the application will affect. You will be able to see the list Activities, Services and Broadcast Receivers, which are registered in the system. This is critical for assessing the impact of the app on the autonomy of the device and the security of personal data.
Particular attention should be paid signature section. The analyzer will show who signed the application. If you downloaded a popular game, and it was signed by an unknown developer or the certificate differs from the original one, this is a sure sign of modification or hacking.
⚠️ Attention: Install only those APK analyzers that have good reviews and do not require unnecessary permissions. Some pseudo-analyzers themselves may be spyware.
Using online services to check security
If you doubt the security of a file and do not want to risk your device by opening it locally, cloud scanners are the best solution. Services like VirusTotal or Hybrid Analysis allow you to download an APK file and scan it with dozens of antivirus engines simultaneously. This is the gold standard for pre-installation checking.
In addition to viruses, such services often provide a "Behavior" or "Details" tab where you can see the network activity that the application is trying to initiate. You'll see what domains it accesses, what permissions it requests, and whether there are any known vulnerabilities in the code. This allows you to look at the file “from the outside” without running it on your device.
Online analysis is also useful because the virus signature databases there are updated hourly, while the local antivirus on the phone may have outdated databases. Uploading the file to the cloud takes time, depending on the Internet speed and the size of the application, but it is worth it for dubious sources.
- ☁️ Go to the site of a verification service (for example, VirusTotal).
- ☁️ Download the APK file through the browser interface.
- ☁️ Wait complete the scan and review the security report.
How safe is it to upload an APK to the cloud?
By uploading a file to public services like VirusTotal, you transfer its sample to the database of antivirus companies. This is safe for ordinary users, but if the APK contains your personal keys or confidential data, it is strictly forbidden to upload such files to the public.
Deep analysis through Dekompiler on a PC
For a professional look “inside” the code, when you need to understand the logic of the app or change resources, mobile tools may not be enough. This is where desktop decompilers come to the rescue, such as JADX, APKTool or Bytecode Viewer. These tools allow you to decompile classes.dex (Dalvik bytecode) back into readable Java code.
The decompilation process requires connecting the phone to the computer or transferring the file to the PC. JADX is one of the most convenient tools as it has a graphical interface and allows you to view the code, resources and manifest in one window. You will be able to see the source code of methods, lines of text, and decision-making logic of the application.
This level is for advanced users and developers. Using such tools, you can find hardcoded API keys, hidden server URLs, or understand how modification protection works. However, it is worth remembering that the code can be obfuscated (confused), and the variables will be named a, b, c, which will make it difficult to understand the logic.
jadx-gui app-release.apkThis command (when using the CLI version) or simply opening the file in the GUI version will allow you to start the analysis. It is important to have an installed environment JDK for most of these utilities to work correctly.
Decompilers on a PC are the only way to see the logic of the application and find hidden code that is not visible when viewing files normally.
Comparison table of viewing methods
To make it easier for you to choose the right one tool, we have prepared a comparison table. It will help you evaluate the pros and cons of each method depending on your goals and level of training.
| Method | Difficulty | Analysis depth | Need a PC |
|---|---|---|---|
| File manager | Low | File structure only | No |
| APK analyzer (App) | Medium | Manifest, permissions, signatures | No |
| Online scanner | Low | Security, viruses, behavior | No (browser required) |
| Decompiler (JADX) | High | Source code, resources, logic | Yes |
The choice of method depends on the task. If you just need to check if it is a virus, an online scanner will suffice. If you need to understand why an application crashes or how it works, you need a decompiler.
Extracting resources and modifying APK
A frequent reason why users want to look at an APK is the desire to get a specific resource: a picture, sound or font. It is difficult to do this using standard means, since resources in Android are compiled into binary format resources.arsc. To extract them and convert them back to PNG or WAV you will need APKTool.
This tool allows you not only to view, but also to decompile and recompile the application. The process requires knowledge of the command line. After parsing, you will receive a folder with decoded resources that can be edited. This is a popular method for localizing games or changing the interface.
⚠️ Attention: Modifying APK files violates the integrity of the digital signature. After any change, the application will not be installed over the original and will require uninstalling the old version, and some protected applications (for example, banking) will simply refuse to launch.
If your goal is simply to save images from a game or application, there are specialized extractor utilities that work faster than full decompilers. They automatically pull out all graphic assets into the gallery.
☑️ Check APK before installation
Frequently asked questions (FAQ)
Is it possible to open an APK file on an iPhone?
No, the operating system iOS uses a completely different application format (.ipa) and architecture. It is impossible to open or run an APK on an iPhone without complex emulation, which in practice is not feasible for the average user.
Is it safe to open an APK through a file manager?
Simply opening the file to view the archive structure is safe, since the code is not executed. However, do not click the "Install" button under any circumstances if you are not sure about the source of the file. Viewing the content does not activate viruses.
Why does the APK file weigh more after renaming it to ZIP?
Usually the weight remains identical, since it is the same file. If the weight has changed, it means that the archive has been compressed or, conversely, metadata has been added by the file manager. In rare cases, some managers may create a copy of the file during conversion.
How to view the Java code inside an APK without a computer?
It is extremely difficult to fully view the decoded Java code on your phone. There are decompiler applications on the Play Market, but they are often unstable or display code in a hard-to-read form. For high-quality code analysis, you still need a PC.
Can an APK file contain a virus if I just looked at it?
No. A virus in an APK is executable code. For it to be activated, the application must be installed and running by the user (or system). Simply opening an archive, renaming or viewing file properties does not lead to infection of the device.