diff --git a/PROJECT.md b/PROJECT.md
index 45ba874..d364e3d 100644
--- a/PROJECT.md
+++ b/PROJECT.md
@@ -42,10 +42,14 @@ The SQLite database is stored on a mounted volume at `/app/data/tracker.db` so i
 ## Key Features
 
 ### Stock Detection
-Puppeteer navigates to each product URL and waits for React hydration (2.5s delay), then:
-- `<button label="Add to Cart">` present → `in_stock`
-- Any `<button>` whose text is `"Notify me when available"`, `"Sold Out"`, or `"Out of Stock"` → `sold_out`
-- Neither found → `unknown`
+Puppeteer navigates to each product URL, waits for React hydration (2.5s + active wait for `<button>` up to 8s), then evaluates with case- and whitespace-insensitive substring matching:
+- Any `<button>` with `label="Add to Cart"` attribute, OR whose text contains `"add to cart"` → `in_stock`
+- Any `<button>` whose text contains one of: `"login for notifications"`, `"login for updates"`, `"notify me when available"`, `"notify me"`, `"sold out"`, `"out of stock"`, `"currently unavailable"`, `"coming soon"` → `sold_out`
+- Neither found → `unknown` (logs a `[Scraper] UNKNOWN debug` payload with page title, button labels, and button texts for diagnosis)
+
+**Two gotchas the matcher handles:**
+- **Auth-state difference.** The scraper runs logged out, so Ubiquiti shows `"Login for Notifications"` on sold-out items instead of the logged-in `"Notify me when available"`. Both must be in the sold-out list.
+- **The `label` attribute exists only on the in-stock button.** Production DOM does carry `label="Add to Cart"` on the primary Add-to-Cart button (confirmed in DevTools), but the sold-out "Login for Notifications" button has no `label` attribute. So in-stock has two redundant signals (attribute + text), sold-out only has text — by design.
 
 Product name is pulled from the `og:title` meta tag (with Ubiquiti store suffix stripped). Thumbnail is pulled from `og:image`.
 
diff --git a/backend/src/scraper.ts b/backend/src/scraper.ts
index a8c76a4..bce585b 100644
--- a/backend/src/scraper.ts
+++ b/backend/src/scraper.ts
@@ -106,7 +106,13 @@ export async function checkStockStatus(url: string): Promise<ScrapeResult> {
         status = 'in_stock';
       } else {
         // Sold-out / unavailable phrases — substring match on normalized button text.
+        // Ubiquiti shows different sold-out text depending on auth state:
+        //   logged out → "Login for Notifications"   (our scraper always sees this)
+        //   logged in  → "Notify me when available"
+        // Both mean the item is unavailable. Keep both, plus common siblings.
         const soldOutPhrases = [
+          'login for notifications',
+          'login for updates',
           'notify me when available',
           'notify me',
           'sold out',