What is the difference between compileSdkVersion and targetSdkVersion?

compileSdkVersion

The compileSdkVersion is the version of the API the app is compiled against. This means you can use Android API features included in that version of the API (as well as all previous versions, obviously). If you try and use API 16 features but set compileSdkVersion to 15, you will get a compilation error. If you set compileSdkVersion to 16 you can still run the app on a API 15 device as long as your app's execution paths do not attempt to invoke any APIs specific to API 16.

targetSdkVersion

The targetSdkVersion has nothing to do with how your app is compiled or what APIs you can utilize. The targetSdkVersion is supposed to indicate that you have tested your app on (presumably up to and including) the version you specify. This is more like a certification or sign off you are giving the Android OS as a hint to how it should handle your app in terms of OS features.

For example, as the documentation states:

For example, setting this value to "11" or higher allows the system to apply a new default theme (Holo) to your app when running on Android 3.0 or higher...

The Android OS, at runtime, may change how your app is stylized or otherwise executed in the context of the OS based on this value. There are a few other known examples that are influenced by this value and that list is likely to only increase over time.

For all practical purposes, most apps are going to want to set targetSdkVersion to the latest released version of the API. This will ensure your app looks as good as possible on the most recent Android devices. If you do not specify the targetSdkVersion, it defaults to the minSdkVersion.

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As a oneliner guide:

minSdkVersion <= targetSdkVersion <= compileSdkVersion

Ideally:

minSdkVersion (lowest possible) <= targetSdkVersion == compileSdkVersion (latest SDK)

Read more from this great post by Ian Lake

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Late to the game.. and there are several great answers above-- essentially, that the compileSdkVersion is the version of the API the app is compiled against, while the targetSdkVersion indicates the version that the app was tested against.

I'd like to supplement those answers with the following notes:

That targetSdkVersion impacts the way in which permissions are requested:

If the device is running Android 6.0 (API level 23) or higher, and the app's targetSdkVersion is 23 or higher, the app requests permissions from the user at run-time.

If the device is running Android 5.1 (API level 22) or lower, or the app's targetSdkVersion is 22 or lower, the system asks the user to grant the permissions when the user installs the app.

If the compileSdkVersion is higher than the version declared by your app's targetSdkVersion, the system may enable compatibility behaviors to ensure that your app continues to work the way you expect. (ref) With each new Android release...

targetSdkVersion should be incremented to match the latest API level, then thoroughly test your application on the corresponding platform version

compileSdkVersion, on the other hand, does not need to be changed unless you're adding features exclusive to the new platform version

As a result, while targetSdkVersion is often (initially) less than than the compileSdkVersion, it's not uncommon to see a well-maintained/established app with targetSdkVersion > compileSdkVersion

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The compileSdkVersion should be newest stable version. The targetSdkVersion should be fully tested and less or equal to compileSdkVersion.

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The CompileSdkVersion is the version of the SDK platform your app works with for compilation, etc DURING the development process (you should always use the latest) This is shipped with the API version you are using

https://i.stack.imgur.com/VE1Mx.png

You will see this in your build.gradle file:

https://i.stack.imgur.com/N8GuB.png

targetSdkVersion: contains the info your app ships with AFTER the development process to the app store that allows it to TARGET the SPECIFIED version of the Android platform. Depending on the functionality of your app, it can target API versions lower than the current.For instance, you can target API 18 even if the current version is 23.

Take a good look at this official Google page.

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I see a lot of differences about compiledSdkVersion in previous answers, so I'll try to clarify a bit here, following android's web page.

A - What Android says

According https://developer.android.com/guide/topics/manifest/uses-sdk-element.html:

Selecting a platform version and API Level When you are developing your application, you will need to choose the platform version against which you will compile the application. In general, you should compile your application against the lowest possible version of the platform that your application can support.

So, this would be the right order according to Android:

compiledSdkVersion = minSdkVersion <= targetSdkVersion

B - What others also say

Some people prefer to always use the highest compiledSkdVersion available. It is because they will rely on code hints to check if they are using newer API features than minSdkVersion, thus either changing the code to not use them or checking the user API version at runtime to conditionally use them with fallbacks for older API versions.

Hints about deprecated uses would also appear in code, letting you know that something is deprecated in newer API levels, so you can react accordingly if you wish.

So, this would be the right order according to others:

minSdkVersion <= targetSdkVersion <= compiledSdkVersion (highest possible)

What to do?

It depends on you and your app.

If you plan to offer different API features according to the API level of the user at runtime, use option B. You'll get hints about the features you use while coding. Just make sure you never use newer API features than minSdkVersion without checking user API level at runtime, otherwise your app will crash. This approach also has the benefit of learning what's new and what's old while coding.

If you already know what's new or old and you are developing a one time app that for sure will never be updated, or you are sure you are not going to offer new API features conditionally, then use option A. You won't get bothered with deprecated hints and you will never be able to use newer API features even if you're tempted to do it.

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My 2 cents: Compile against any version of the SDK but take care not to call any APIs that your "minimum SDK version" does not support. That means you "could" compile against the latest version of the SDK.

As for "target version" it simply refers to what you planned to target in the first place and have possibly tested against. If you haven't done the due diligence then this is the way to inform Android that it needs to perform some additional checks before it deploys your lets say "Lollipop" targeted app on "Oreo".

So the "target version" is obviously not lower than your "minimum SDK version" but it can't be higher than your "compiled version".

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Not answering to your direct questions, since there are already a lot of detailed answers, but it's worth mentioning, that to the contrary of Android documentation, Android Studio is suggesting to use the same version for compileSDKVersion and targetSDKVersion.

https://i.stack.imgur.com/lxWp6.png

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compiledSdkVersion==> which version of SDK should compile your code to bytecode(it uses in development environment) point: it's better use last version of SDK.

minSdkVersion==> these item uses for installation of APK(it uses in production environment). For example:

if(client-sdk-version   <   min-sdk-versoin )
    client-can-not-install-apk;
else
    client-can-install-apk;

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The Application settings of an Android project's properties in Visual Studio 2017 (15.8.5) has them combined:

https://i.stack.imgur.com/RkYRn.png

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Quick summary:

For minSDKversion, see latest entry in twitter handle: https://twitter.com/minSdkVersion

TargetSDKversion: see latest entry in twitter handle: https://twitter.com/targtSdkVersion or use the latest API level as indicated at devel https://developer.android.com/guide/topics/manifest/uses-sdk-element.html

Compiled version: make it same as TargetSDKversion

maxSdkVersion: advice from Android is to not set this as you do not want to limit your app to not perform on future android releases

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