JLPT is also known as Japanese Language Proficiency Test. JLPT tests are held in Japan and throughout the world. It is usually offered twice in July and December of the year. In some locations, the JLPT tests are only offered in December.
There are 5 different levels for JLPT. JLPT N1 is the highest level and JLPT N5 is the lowest level. JLPT N1 assumes you have advanced Japanese language skills and can communicate fairly extensively. JLPT N5 assumes you have basic Japanese language skills and you know basic Japanese greetings and words.