B4A File

What are B4A files and how to open them

Are you having problems opening a B4A file or are you simply curious about its contents? We're here to explain the properties of these files and provide you with software that can open or handle your B4A files.

What is a B4A file?

A .B4A file is a B4A Application file.

B4A Application files store the source code for an app project created with Basic4Android (now called B4A), a rapid application development tool for native Android applications. These files embed the main activity module code along with project attributes (like application label, version, supported orientations) and default code stubs for lifecycle methods such as Activity_Create, Activity_Resume, Activity_Pause.

A B4A Application source file is produced and edited within the B4A IDE on Windows. When compiled, the IDE converts the code into Java and XML manifest files, packages them into a native APK, and places intermediate build artifacts into project subfolders such as Objects. Other modules not part of the main activity are stored as separate files alongside the primary B4A application file.

Internally the file is plain text encoded (often UTF-8 with a BOM), and contains recognizable keywords and region markers such as ApplicationLabel, VersionCode, VersionName, Sub Activity_Create(FirstTime As Boolean), Sub Process_Globals, SUB ACTIVITY_PAUSE (UserClosed As Boolean), TARGETSDKVERSION, USES-SDK ANDROID among others. A leading byte signature EF BB BF at offset 0 (UTF-8 BOM) is common.

How to open B4A files

Important: Different programs may use files with the B4A file extension for different purposes, so unless you are sure which format your B4A file is, you may need to try a few different programs.

While we have not verified the apps ourselves yet, our users have suggested two different B4A openers which you will find listed below.

Last updated: August 22, 2026

Various apps that use files with this extension

These apps are known to open certain types of B4A files. Remember, different programs may use B4A files for different purposes, so you may need to try out a few of them to be able to open your specific file.

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File.org helps thousands of users every day, and we would love to hear from you if you have additional information about B4A file formats, example files, or compatible programs. Please use the links below or email us at submit@file.org to discuss further.