CORS in NodeJS What is CORS? Cross origin Resource Sharing is a mechanism of sharing the resources like images, API, styles, fonts, audio, video, etc from another domain. By default any browser has same-origin policy, which restricts the browser to access all content from its own domain. But, what if browser want to excess data from other domain? For Example: If domain1.com wants to call API which is defined in domain2.com, then domain1.com has to by pass its same-origin policy to cross-origin policy. Why CORS? CORS defines who can access what , and thus securing the domain. It can be dangerous if CORS enables to access API to everyone. How to use it in Nodejs? Method 1: const app = express(); app.use(function (req, res, next) { res.header("Access-Control-Allow-Origin", "*"); //Allow access to everyone res.header("Access-Control-Allow-Origin", "http://domain1.com"); //Allow access to domain1 }); Method 2:...