Some common varieties of hot peppers, from mild to hottest, include banana peppers, shishito peppers, jalapeño peppers, habañero peppers and cayenne chili peppers. Some hotter varieties are the Thai dragon, the ghost pepper, the infinity chili pepper, the Naga Viper and the Carolina Reaper.
Banana and shishito peppers are mild, ranging from 0 to 1,000 Scoville units, the unit of measure for pepper hotness. Jalapeño peppers are medium hot peppers, while the infinity chili pepper and the Naga Viper are very hot, at more than 1 million Scoville units. Hot peppers have multiple uses, from adding flavor or a little kick when cooking to inspiring pepper-eating competitions. Peppers get their spice from the capsaicin in the seeds and ribs of the pepper. The more capsaicin, the hotter the pepper.