Briefmarken Klein is an online shop serving stamp collectors, offering a broad selection of individual stamps, complete year sets, collections and related collectibles. Its catalogue spans Germany, including the former German states, the German Empire, post-war zones, the Federal Republic, Berlin and the GDR, as well as Austria, Switzerland, Liechtenstein, the Soviet Union and countries across Europe, Asia and overseas. Collectors can browse by country, period, format, condition or theme, with listings for mint and used stamps, miniature sheets, booklets, pairs, coil stamps, errors, postal stationery, letters and postcards.

The shop also offers lots, partial collections, complete collections and rarities, alongside coins, banknotes and other collecting items. Customers can search by collecting area, review weekly offers and clearance items, and purchase gift vouchers. Briefmarken Klein positions its assortment as a place to find additions for established collections or discover new collecting interests.

Online account features let customers review previous orders and make future purchases more quickly; the shop also provides information about shipping and delivery, contact and help