Vaccination in Bali is not mandatory. However, this does not mean that you should not be vaccinated at all. The basis should be vaccination against jaundice type A and for greater peace of mind when you eat at street stalls also against typhoid fever. It depends a lot on your travel plans and how you spend your stay. For example, in case of closer contact with dogs or monkeys, rabies vaccination may be useful. Be sure to consult your doctor or vaccination center. However, it is ONLY what you decide on.
You can check the timeliness of the information before traveling on the website of the Ministry of Health.