Is key case sensitive?

While object properties are strings and they are case sensitive , you could use an own standard and use only lower case letters for the access. You could apply a String#toLowerCase to the key and use a function as wrapper for the access.

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What is key in map Salesforce?

A map is a collection of key-value pairs where each unique key maps to a single value . Keys and values can be any data type—primitive types, collections, sObjects, user-defined types, and built-in Apex types. Map keys and values can contain any collection, and can contain nested collections.

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