API level

Android API is framework by which app can interact with android OS
Its like permissions like to access Internet,Read/Write Sd,Controling sensors etc. Even I dont knon much about it, an ask expert for more detailed explanation

api level is the numeric code for the android version.

coding wise its most commonly used in the android manifest.

android:minSdkVersion="11"
android:targetSdkVersion="24" /> this tells the application it requires at least version 11, and can target up to version 24.

it comes into play as well if you are trying to use features specific to later versions of the api, you can query the build version so that you can avoid trying to use a feature beyond what is available, and thusly avoid crashing.

if(Build.VERSION.SDK_INT >= 16) // like that.. this if statement will only ring true if the build version is greater than or equal to api level 16

here is a handy dandy list of what the api level numbers relate to
Marshmallow 6.0 API level 23
Lollipop 5.1 API level 22
Lollipop 5.0 API level 21
KitKat 4.4 - 4.4.4 API level 19
Jelly Bean 4.3.x API level 18
Jelly Bean 4.2.x API level 17
Jelly Bean 4.1.x API level 16
Ice Cream Sandwich 4.0.3 - 4.0.4 API level 15, NDK 8
Ice Cream Sandwich 4.0.1 - 4.0.2 API level 14, NDK 7
Honeycomb 3.2.x API level 13
Honeycomb 3.1 API level 12, NDK 6
Honeycomb 3.0 API level 11
Gingerbread 2.3.3 - 2.3.7 API level 10
Gingerbread 2.3 - 2.3.2 API level 9, NDK 5
Froyo 2.2.x API level 8, NDK 4
Eclair 2.1 API level 7, NDK 3
Eclair 2.0.1 API level 6
Eclair 2.0 API level 5
Donut 1.6 API level 4, NDK 2
Cupcake 1.5 API level 3, NDK 1
(no code name) 1.1 API level 2
(no code name) 1.0 API level 1

typically I don't go too much further below api level 11, just due to the kinds of things I am making

-MunkeeBonez