Path Parameter

ELI5 — The Vibe Check

A path parameter is a variable embedded directly in the URL path. Instead of '?id=5', you put the value right in the path: '/users/5'. It usually identifies a specific resource. Path params are cleaner-looking than query strings for resource IDs.

Real Talk

Path parameters are variable segments in a URL path used to identify specific resources in REST APIs. Defined with colons in route patterns (e.g., /users/:id), they're extracted by the server for processing. Unlike query strings, they're part of the resource identifier.

Show Me The Code

// Express.js path parameters
app.get('/users/:userId/posts/:postId', (req, res) => {
  const { userId, postId } = req.params;
  // GET /users/42/posts/7 → userId='42', postId='7'
  res.json({ userId, postId });
});

// REST design convention:
// GET /products/123        → get product 123
// PUT /products/123        → update product 123
// DELETE /products/123     → delete product 123

When You'll Hear This

"Use a path parameter for the user ID in the REST endpoint." / "The path parameter is undefined — check the route definition."