External Middleware in Express.js with Example

What is External Middleware in Express.js?

  1. External middleware is not built into Express.js.
  2. You must install it separately via npm.
  3. It adds extra functionality (like logging, CORS, authentication, etc.)


Example: morgan Middleware

  1. morgan is an external middleware used for logging HTTP requests in the terminal.
  2. Helpful for debugging and monitoring incoming requests.


Steps to Use Morgan Middleware


1. Install morgan

npm i morgan


Import it

import morgan from "morgan";


Use it in your Express app

app.use(morgan("dev"));
"dev" is a predefined format that logs method, URL, status code, response time, etc.


Example Output in Terminal

GET / 200 2.012 ms - 9
GET /login 200 1.223 ms - 12
GET /random 404 3.314 ms - 142


To Verify Time Logging

Add a route with a delay:

app.get("/wait", (req, resp) => {
setTimeout(() => {
resp.send("result after 1 sec");
}, 1000);
});


Now open:

http://localhost:3200/wait


Output in Terminal:

GET /wait 200 1011.997 ms - 18

Shows accurate request timing.