ActiveFilterable is a gem designed to enable custom query filters for ActiveRecord models through metaprogramming. By using ActiveFilterable, you can specify which attributes of a model can be used for filtering and define different query methods such as full-text matching, prefix matching, suffix matching, IN queries, NOT IN queries, equality, greater than, less than, not equal, greater than or equal to, and less than or equal to. ActiveFilterable provides a concise and flexible way to handle complex query requirements. It allows you to define query filters directly in the model and apply them by chaining method calls in the controller, generating the corresponding query conditions.