An important and common feature shared in common by both Judaism and Zoroastrianism is that they rae monotheistic, in a time when all other religions were polytheistic.
Judaism appeared in the Middle east nearly 4,000 years ago and has been based on the worshiping of only one deity, YHW (ancient Hebrew had no written vowels, and it has been speculated that this name sounded like "YAHWE"), and this belief has fiercely been upheld and defended by Judaism practitioners.
Zoroastrianism, in turn, emerged in ancient Persia as a follow-up of a cult of the Sun God Mithra, a cult monotheistic cult, too. Both cults co-existed for some time, but followers of Zoroastrianism campaigned to drop the cult of Mithra and keep the cult of Ahura-Mazda, the god of Zoroastrianism which is also called "Mazdaism" in account of Ahura-Mazda. Throughout its history. Zoroastrianism has been on the verge of disappearing with the successive advent of Christianity and Islam, and even though its number of practitioners is relatively small, it has managed to survive to this day.