Postikadi (ing. post card) ni aina ya barua isiyo na bahasha. Kwa kawaida ni kipande cha kistatili cha karatasi chenye ujumbe mfupi unaotumwa kwa posta. Mara nyingi postikadi huwa na picha upande mmoja halafu anwani, stempu na ujumbe mfupi upande wa kinyume. Gharama ya postikadi ni kidogo chini ya gharama ya barua katika bahasha. Ilhali postikadi haina bahasha ujumbe wake unaweza kusomwa na kila mtu anayeishiska. Kadi hizi zilianza kutumiwa kuanzia miaka ya 1860. Tangu kuwa na bei ndogo kuliko barua idadi ya postikadi kati ya barua iliongezeka. Baada ya kupatikana kwa simu za mkononi, sms na barua pepe postikadi zimepungua sana. Bado zinatumiwa hasa na watu waliosafiri wakitaka kutuma picha ya mahali walipofika. The Postcard Traders association—Represents professionals within the UK postcard industry. The International Federation of Postcard Dealers—Represents professional postcard dealers worldwide. Japanese Postcard Collecting Research きのう屋日本の絵葉書コレクション Postcards Collection - The collection of postcards from around the world Bowden Postcard Collection Online. Approximately 10,000 digitized postcards, maintained by the Walter Havighurst Special Collections in the Miami University Libraries. abadie.co.uk, currently the only book of classic John Hinde postcards with the senders messages transcribed johnhindecollection.com, a website dedicated to John Hinde Postcards Plowman Family Postcard Collection.