What is the difference between path parameters and query parameters?

Path parameter and query parameter are two ways of passing data in a URL, but they differ in purpose and syntax.

• Path parameter is part of the URL path, used to identify a specific resource. For example, in the URL /users/123, the number 123 is a path parameter representing the user ID.

• Query parameter are parameters passed after the ? sign in the URL, usually for filtering, sorting, or passing additional options. For example, /users?sort=asc&limit=10 — here, sort and limit are query parameters.

Example:

GET /products/45         # path parameter: 45 — product ID
GET /products?category=books&price_lt=100  # query parameters: filters

Thus, path parameters are usually mandatory and define the resource, while query parameters are optional and refine the request.