Index is a data structure (like dictionary) that improves the speed of data retrieval operations on a database table at the cost of additional writes and storage space. Indexing involves creating an organized structure that allows the database management system (DBMS) to locate and access rows more efficiently based on the values in one or more columns.

A table contains data, a view is just a SELECT statement which has been saved in the database (more or less, depending on your database).

REST API (Representational State Transfer Application Programming Interface) is an architectural style for designing networked applications. It is a set of constraints or principles that define how resources should be represented and addressed in a distributed and stateless manner. REST is not a specific technology but rather a set of architectural principles commonly applied to web services.