HTTP requests and responses: Using the hypertext transfer protocol (HTTP), information request messages are sent from a client to a server which in turn makes a response to the client.
HTTP headers: An HTTP header contains fields that describe certain characteristics of an HTTP request/response, such as content-type.
HTTP response codes: There are five different ranges of HTTP status codes, defining different aspects of the transaction process between the client and the server. These are: 1-1xx -Informational 2-2xx-Success 3-3xx-Redirection 4-4xx-Client error 5-5xx-Server error.
HTTP basic auth: With basic authentication, you can put the username and password in the URL, or you can add them in an Authorization header of each request.
What is a cookie?
Cookies are simple text files that contain two pieces of information: a website name and a unique identifier of some sort. This identifier could be a number or an alphanumeric string. When you visit a cookie-using website for the first time, it places a cookie in your web browser. When you visit this website again, it looks for the cookie so that it can tell whether you have visited before and how to best improve your experience for your latest visit.
AJAX / JSONP: AJAX stands for Asynchronous JavaScript And XML. AJAX allows web pages to be updated asynchronously by exchanging data with a web server behind the scenes. This means that it is possible to update parts of a web page, without reloading the whole page. JSONP provides a method to request data from a server in a different domain, something prohibited by typical web browsers because of the same origin policy. It does this by wrapping the desired domain in a callback function.
ReST (and how it compares to SOAP, Graph, etc.): REST (Representational State Transfer) describes the general rules for how data and services are represented through an API so that other programs will be able to correctly request and receive that data and those services that an API makes available. ReST is an architectural style and SOAP is a protocol, which can technically be used within the ReST system. That said, ReST uses HTTP to communicate while SOAP uses XML.
Asynchronous ReST: Most ReST-ful communications handle asynchronicity with the use of a callback function. This callback function includes two parameters--response data and error data. Depending on the response, a conditional will either handle an error or process the data on success.