What's difference with express-session and cookie-session?

Solution 1:

Basically, express-session is more abstract, it supports different session stores (like files, DB, cache and whatnot).

And cookie-session is a simple / lightweight cookie-based (cookie is the only storage engine supported: all the session info is stored on the client, in a cookie) session implementation. This kind of sessions is probably most famous for its Rails implementation.

Solution 2:

The basic difference between both these relates to how and where is the session data being stored. Cookie session is basically used for lightweight session applications where the session data is stored in a cookie but within the client [browser], whereas, Express Session stores just a mere session identifier within a cookie in the client end, whilst storing the session data entirely on the server. Cookie Session is helpful in applications where no database is used in the back-end. However, the session data cannot exceed the cookie size. On conditions where a database is used, it acts like a cache to stop frequent database lookups which is expensive.