Postman makes it easy to exercise every route you build in Express without writing a frontend first. Here's a walkthrough for a small inventory service.
Prerequisites
- Node.js and npm
- Express
- Postman installed
Step 1: Set up the project
mkdir inventory-service
cd inventory-service
npm init -y
npm install express
Step 2: Create the server file
touch server.js
Step 3: Write the routes
// server.js
const express = require("express");
const app = express();
const PORT = 5000;
app.use(express.json());
app.get("/", (req, res) => {
console.log("GET request handled");
res.send("Inventory Service is running");
});
app.post("/items", (req, res) => {
console.log("POST request handled", req.body);
res.send("Item created");
});
app.put("/items/:id", (req, res) => {
console.log("PUT request handled", req.body);
res.send(`Item ${req.params.id} updated`);
});
app.delete("/items/:id", (req, res) => {
console.log("DELETE request handled");
res.send(`Item ${req.params.id} deleted`);
});
app.listen(PORT, () => {
console.log(`Server listening on ${PORT}`);
});
Step 4: Run the server
node server.js
Step 5: Test each route in Postman
| Method | Endpoint | Purpose |
|---|---|---|
| GET | localhost:5000/ | Health check |
| POST | localhost:5000/items | Create an item |
| PUT | localhost:5000/items/1 | Update item with id 1 |
| DELETE | localhost:5000/items/1 | Delete item with id 1 |
For POST and PUT, set the request body to raw JSON, e.g. { "name": "Notebook", "qty": 10 },
and Postman will show the response text your server sends back.