Mention what is the difference between the Observers and Callbacks in Ruby on Rails?

The main differences between Observers and Callbacks in Ruby on Rails are:

Observers are external to the model class and react to changes within the model, keeping the model's core responsibilities clean[1][2]. Callbacks are methods called at certain points in an object's lifecycle and are integral to the model[1]. Observers are best for complex, multi-model operations, while Callbacks are ideal for straightforward, model-specific tasks[1].

Observers maintain a clear separation of concerns between the model's responsibilities and reactions to its changes[1]. They are versatile, capable of reacting to changes across multiple models[1]. Callbacks can pollute a model with code not directly related to its purpose[2].

Observers are conventionally placed in the app/models directory and registered in config/application.rb[2]. Callbacks are defined directly within the model clas...