File Extension Library

.OAT File Extension

  • Developer by: Google
  • Category: Developer Files

What are .OAT files and how to open them?

Can't open .OAT file? Are you wondering what it contains? On our site we will explain to you what this file is, what it is used for and what software opens the .OAT file.

What is a .OAT file extension?

.OAT file extension is created by Google. .OAT has been classified as Developer Files.

.OAT is Android Optimized Application File

An OAT file is created by the Android operating system in order to speed up the loading time of an Android app (.APK file). When an app is installed, Android automatically optimizes app data and creates a corresponding OAT file. Android uses this file to load the app more quickly, which creates a better experience for the user.

OAT files are typically saved to the following directory on the Android device:


Android performs these optimizations using a tool called dex2oat. When you install an application on a device running Android 5.0 or later, dex2oat converts the Dalvik code located in the .ODEX file to native code and stores it in an OAT file. Therefore, each app will have a corresponding OAT file. dex2oat is typically located in the following directory on the Android device:


NOTE: OAT files were introduced with Android 5.0, which is codenamed “Lollipop" or “L.” Previous versions of Android use .ODEX (Optimized DEX) files instead of OAT files for optimized executables. The new Android 5.0 runtime, called ART (Android Runtime), uses an ahead-of-time (AOT) compilation method, which improves upon its predecessor’s method of just-in-time compilation. ART replaces the previous runtime, which is called Dalvik.

Common OAT Filenames

boot.oat - This file is created whenever a device's system is upgraded or when the app is booted up for the first time after being purchased. The boot.oat file is referenced by an app when the app calls a framework application programming interface (API) method.

List of all softwares that can open the Android Optimized Application File
Google Android

How to fix problems with .OAT files

  1. You need to update the application that you normally use to open .OAT files. Only the latest version of the software supports the current .OAT file format
  2. You need to check the .OAT file for viruses. To do this, you need to scan it with a popular antivirus (Norton, Nod32, Kaspersky, Dr.Web, etc.)