Route Parameters

Sometimes you need dynamic routes that change based on input, such as an ID.

Express allows you to define route parameters using :.

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

  res.send(`User ID is ${userId}`);
});

Here, :id is a dynamic value. When a request comes in, Express extracts it and makes it available in req.params.

For example:

• '/users/1': id = 1;
• '/users/42': id = 42.

This is commonly used to get specific data, such as a user by ID or a product by ID.