Āpta (Apta) is a Nāga (Naga; Snake), one of the sons of Kadrū (Kadru), sired by Prajāpati (Prajapati; Ruler of the people) Kaśyapa (Kasyapa).
In Udyogaparva(Udyogaparva) of Mahābhārata (Mahabharata), Nārada (Narada), while visiting Bhogavatī Purī (Bhogavati Puri; the city of Bhogavati) tells Mātali(Matali) about the distinguished Nāgas residing there. In this course, he has also mentioned the name of Āpta(Apta).