#25 Difference between params and query

Difference Between Params and Query in URL (and React/Express)

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🔹 1. Params (Route Parameters):

• Part of the URL path
• Used to identify a specific resource
• Defined with : in route (e.g., /user/:id)
• Accessed using req.params in Express

Example:

// URL: /user/42
<Route path="/user/:id" element={<User />} />

In backend (Express):

app.get('/user/:id', (req, res) => {
  console.log(req.params.id); // 42
});

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🔹 2. Query Parameters:

• Appended to the URL after ?
• Used for filtering, sorting, or searching
• Multiple key-value pairs with &
• Accessed using req.query in Express

Example:

// URL: /search?term=react&page=2

In backend:

app.get('/search', (req, res) => {
  console.log(req.query.term); // react
  console.log(req.query.page); // 2
});

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✅ Summary:

• Params are part of the route and usually identify resources.
• Query is for optional filters or metadata, not part of route structure.