A REST API receives data in many places: URL path, query string, body, headers, cookies. This article covers every way to extract that data in Spring MVC. @PathVariable — Extract from URL Use @PathVariable when the data is part of the URL path: // URL: GET /api/orders/550e8400-e29b-41d4-a716-446655440000 @GetMapping("/{id}") public OrderResponse getOrder(@PathVariable UUID id) { return orderService.findById(id) .map(OrderResponse::from) .orElseThrow(() -> new OrderNotFoundException(id)); } Spring automatically converts the string segment to the parameter type (UUID, Long, int, etc.