Multi-Product Comparator by twttr

When comparing several products, there's no built-in way to see which shops stock all of them. Multi-Product Comparator lets you add products to a compare list and highlights shops that carry every added item — directly on the offer list.

How it works:
1. Visit a product page on a supported site
2. Click "Add to Compare" (floating panel, bottom-right)
3. Open another product page — shops carrying all your added products are highlighted in green
4. Manage the list on the page or via the toolbar popup

Supported sites:
• idealo — idealo.de, idealo.at, idealo.fr, idealo.es, idealo.it, idealo.co.uk
• Geizhals — geizhals.de, geizhals.at, geizhals.eu, skinflint.co.uk, cenowarka.pl
• billiger.de
• guenstiger.de

Each site keeps its own separate compare list. UI is localized (German, English, French, Spanish, Italian, Polish). Your list lives in session storage only — it clears when you close the browser. No accounts, no tracking, no data collection.