Convert OBB to APK

A device or installer may accept only an APK even when an Android game supplies a separate OBB expansion file. The files are not interchangeable: install the matching APK and OBB, or rebuild the application from source with the expansion data included.

What the OBB format is

OBB is an Android expansion-file format used for large application assets such as 3D models, maps, audio, video, and game data. Older Google Play expansion packages and games built with Unity or other engines commonly use it; newer Google Play apps often use Play Asset Delivery instead.

An OBB normally contains data rather than executable application code, an Android manifest, permissions, or installable package metadata. Its filename is usually tied to the package name and version, for example main.123.com.example.game.obb or patch.123.com.example.game.obb. The expected location is Android/obb/<package-name>/.

Some OBB files are ZIP-compatible and can be inspected or extracted with 7-Zip, but OBB is not an APK variant. Extraction does not create an installable package, and an OBB may use a proprietary or encrypted layout.

What the APK format is

APK is Android's installable application-package format. It normally contains compiled code, resources, an Android manifest, native libraries when required, and signing information. Android Package Manager can install it after validating its package structure and signature.

An APK is ZIP-based, so renaming file.obb to file.apk does not add the missing code, manifest, or signature. An APK can still require a separate OBB at runtime. Some current applications are distributed as split APKs generated from an Android App Bundle and require several APK files installed together.

An APK is useful for sideloading, archiving, and installing the application package itself; it is not necessarily a self-contained copy of all application data.

How to use an OBB with its APK

There is no reliable generic OBB-to-APK converter. For a supplied APK and OBB, preserve both files and install them as a matching set.

1. Install the APK with Android Package Installer, or use adb install app.apk. For split packages, use adb install-multiple base.apk split_*.apk with all required APKs.
2. Confirm the package name and version. On a desktop, aapt dump badging app.apk or Android SDK apkanalyzer can show package metadata.
3. Create /sdcard/Android/obb/<package-name>/ on the device and copy the matching OBB there without changing its filename. A typical ADB sequence is adb shell mkdir -p /sdcard/Android/obb/com.example.game followed by adb push main.123.com.example.game.obb /sdcard/Android/obb/com.example.game/.
4. Start the application. The OBB's package name, version number, filename, and expected directory must match the installed application; otherwise it may report missing or incompatible data.

Android 11 and later restrict ordinary file-manager access to Android/obb. Use the game's supported installer, ADB, or a file manager that has an authorized system file-access method; access restrictions vary by Android version and device manufacturer.

How to make one APK from the data

For an application you own or are authorized to modify, rebuild it from the original Android Studio project rather than converting the binary OBB.

1. Extract the OBB with 7-Zip if it is readable, then place the required assets in app/src/main/assets/ or an appropriate resource directory.
2. Change the application code to read the new internal asset paths instead of Android/obb/.
3. Adjust Gradle packaging, compression, and asset-delivery settings for the added files.
4. Build with ./gradlew assembleRelease, then sign the output with Android Studio's Build → Generate Signed Bundle/APK or the Android SDK's apksigner.
5. Test the signed APK on the target Android versions, screen configurations, and CPU architectures.

If only compiled files are available, apktool can decode and rebuild some APK resources and 7-Zip can inspect archives, but neither converts an OBB into an APK. Decompiled code can be incomplete, native libraries need separate handling, and original signing keys, source code, build configuration, and server-side dependencies may be unavailable.

Compatibility and quality limits

Embedding expansion data can make the APK too large for the intended distribution channel, increase installation time, duplicate compression, and break code that expects a particular expansion-file path. The OBB may also be encrypted, version-locked, architecture-specific, or dependent on licensing and online services.

A rebuilt APK must be signed. A new signing key cannot update an existing installation signed with a different key, so the original application may need to be uninstalled, which can remove its private data. Repackaging can also fail because of Google Play licensing, integrity checks, split-APK dependencies, native libraries, or server validation.

No reputable online converter can generically supply the missing application code and package metadata. Online archive tools may display a ZIP-compatible OBB, but uploading commercial game data or private assets can disclose copyrighted or confidential files. Use 7-Zip for inspection, Android Studio for an authorized rebuild, and ADB or the application's installer for deployment.