How to fix the Express req.body undefined error

In this tutorial, we will learn how to fix the req.body undefined error in express.

Consider, we have a /users route in our express app.

const express = require("express");
const app = express();

app.post("/users", (req, res) => {
  console.log(req.body);
});

app.listen(3000, () => console.log(`App is running`));

Now, if we send a JSON data to the /users route, we will see an undefined in the console.

To fix this error, first we need to parse our incoming requests by using the express.json() , express.urlencoded() middleware functions.

const express = require("express");
const app = express();

// middleware
app.use(express.json());
app.use(express.urlencoded());

app.post("/users", (req, res) => {
  console.log(req.body);
});

app.listen(3000, () => console.log(`App is running`));

Note: Always add your routes after the middleware functions, like in the above code.