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Instead of providing a class concept, in prototype-based programming, an object is linked to another object, called its prototype or parent. In Self, an object may have multiple or no parents,cite-ref-46[46] but in the most popular prototype-based language, JavaScript, an object has exactly one prototype link, up to the base object whose prototype is null.

A prototype acts as a model for new objects. For example, if you have an object fruit, you can make two objects apple and orange that share traits of the fruit prototype. Prototype-based languages also allow objects to have their own unique properties, so the apple object might have an attribute sugar_content, while the orange or fruit objects do not.

Some languages, like Go, don't support inheritance.cite-ref-47[47] Instead, they encourage "composition over inheritance", where objects are built using smaller parts instead of parent-child relationships. For example, instead of inheriting from class Person, the Employee class could simply contain a Person object. This lets the Employee class control how much of Person it exposes to other parts of the program. Delegation is another language feature that can be used as an alternative to inheritance.

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