SPA stands for Single Page Application, and is a web application that functions on one page in the browser. They exist to give the feeling of a desktop app, and a smoother experience. read more
AJAX (asynchronous JavaScript and XML) describes the process of making these partial content requests/responses to the web server. I would have to say the primary difference is that an SPA is a paradigm for development of a web page or application. read more
A good AJAX implementation is about 28 lines Angular is about 28 thousand lines. Imagine someone asking you, what is the difference between a screw driver and a toolbox. That. Exactly. read more
AJAX, Asynchronous Javascript and XML. This is executed client side in browswer and makes requests to the server for specific information. The information returned from the server needs to be handled on the client machine with javascript. read more