Postcardware, also called just cardware, is a style of software distribution similar to shareware, distributed by the author on the condition that users send the author a postcard. The concept was first used by Aaron Giles, author of JPEGView. Another well-known piece of postcardware is the roguelike game Ancient Domains of Mystery, whose author Thomas Biskup collects postcards from around the world. This is similar to beerware.

A variation, Emailware, uses the same approach but requires the user to send the author an email.

Postcardware, like other "novelty" software distribution terms, is not usually enforced.

Software distribution

Cardware | Carticiel | Cardware | Postcardware