Short Code - A Short Code (also known as short numbers) is a five-digit number provided by mobile operators on which users can send SMS's. The general idea behind short codes is that they are easier to remember and hence, solicit more responses than regular numbers, and let users interact with companies.
Short codes are often used with automated services, which can handle instant queries. It can be used by sending message to an associated short code number by typing the keyword and message with space separation. The service then responds to the command appropriately.
Long Code - Long Code is a 10-digit virtual Mobile Number, where a user can send a text message to interact with applications and get the desired response. It works with SMS based applications to pull information from any type of database.
Keyword - Keyword is a combination of alphabets, any brand name or alphanumeric characters. As Short codes/Long Code are shared and are used by many clients at same time. In order to identify which SMS has come for a specific client it is done with the help of keyword. Keyword is prefixed to the message sent by the sender and application software filters the records for clients. Example of keyword: KBC2 or RESULT < space > MBA.