Vanilla Android is an unmodified version of Android.
Vanilla is the base for all versions of Android, with each vendor then adding their own modifications to create a unique flavor. The most popular vanilla version was created by Google and made available as open source on August 15, 2008 under the Apache license: this release became known as “Android Open Source Project” or AOSP (A-OS-P).
AOSP contains only those components necessary for running an operating system that are developed in collaboration with third parties such as hardware manufacturers and wireless carriers; it does not contain any proprietary software from these groups. Many vendors use the AOSP codebase to run customized mobile devices at lower prices while still providing quality products like Samsung Galaxy series phones.