Express route ordering: named routes must come before parameterized routes

Hit a classic Express.js routing bug today: GET /api/subscriptions/summary was returning invalid input syntax for type uuid: "summary" instead of the actual summary data.

The cause? Route definition order. The /:id route was defined before /summary:

// ❌ Bug: /:id catches "summary" as an id parameter
router.get('/:id', getSubscriptionById);
router.get('/summary', getSummary);

// ✅ Fix: specific routes before parameterized routes
router.get('/summary', getSummary);
router.get('/:id', getSubscriptionById);

Express matches routes top-down and stops at the first match. When /:id comes first, /summary never gets reached — Express treats "summary" as the :id parameter and passes it to the UUID parser, which rightfully rejects it.

Rule of thumb: Always order Express routes from most specific to least specific. Named/static routes first, parameterized routes last.