Req

Express v4 requires extra middle ware to handle POST requests

app.use(bodyParser.json());

Express in 4.16 again has express.json()

app.use(express.json({ limit: "1GB" })); //default limit 100kb

Access

req.query //query parameters
req.body //post body
req.params //url variables like /user/:userid

Advanced

Get Ip Address

const ip =
      req.headers["x-forwarded-for"] ||
      req.connection.remoteAddress ||
      req.socket.remoteAddress ||
      (req.connection.socket ? req.connection.socket.remoteAddress : null);

Headers

req.headers

See forms for how to do multipart forms for binary/form data