The various differences between "either" and "too" will be explained with some examples so that you can have a better understanding of how these words are used. "Too" is an adverb, which means likewise. It is used to affirm that a particular feature or anything about object A is common to object B. For example, I like eating warm food, and my brother likes it too. It can also be used to contradict a negative assertion. In other words, this word is used in positive statements.
On the other hand, either can be used to perform the function of an adverb. As an adverb, it is used in negative statements. For example, He doesn't like me, and I don't like her either. As a determiner, it means anyone, especially when talking about two things. For example, you can do it either way. At times, when either is used, it goes together with "or." For example, Either you stay here till tomorrow, or you go now.