Express Routing Basics: Methods and Paths

Express Routing Basics: Methods and Paths

Routing in Express maps HTTP methods and URL paths to handlers. Here is how it works.

Basic Routes

app.get('/users', (req, res) => { /* list users */ });
app.post('/users', (req, res) => { /* create user */ });
app.put('/users/:id', (req, res) => { /* replace user */ });
app.patch('/users/:id', (req, res) => { /* update user */ });
app.delete('/users/:id', (req, res) => { /* delete user */ });

HTTP Methods

• GET: read data. Should be safe (no side effects) and idempotent.
• POST: create a new resource.
• PUT: replace a resource (full update).
• PATCH: partial update.
• DELETE: remove a resource.

URL Params

Use :name for params: /users/:id. Read them with req.params.id. Params are strings.

app.get('/users/:id', (req, res) => {
  res.json({ id: req.params.id });
});

Query Strings

Anything after ? is in req.query: /users?search=foo&limit=10 gives req.query = { search: 'foo', limit: '10' }. Always strings; coerce when needed.

Wildcards

Use * for matching anything: app.get('/users/*', ...) matches /users/abc/def. Useful for catch-alls.

Multiple Handlers

A route can have multiple handlers, each calling next:

app.get('/posts/:id', authenticate, loadPost, (req, res) => {
  res.json(req.post);
});

This is how you compose middlewares per route.

express.Router

For grouping routes by feature, use express.Router:

// routes/users.js
const router = express.Router();
router.get('/', listUsers);
router.post('/', createUser);
router.get('/:id', getUser);
module.exports = router;

// app.js
app.use('/users', require('./routes/users'));

This mounts all user routes under /users. Cleaner than putting every route in app.js.

The Takeaway

Express routing maps HTTP methods and paths to handlers. Methods: GET, POST, PUT, PATCH, DELETE. Use :name for URL params, ?key=value for query strings, and express.Router to group routes by feature. Multiple handlers per route enable per-route middleware composition.