If you want to visit Indonesia for a prolonged period for the purpose of doing business activities then the business visa is a solution. There are two types of business visa: (1) the singly entry business visa and (2) the multiple entry business visa. The singly entry business visa is initially valid for 30 days. However, you can extend it twice, each time by one month, hence you can stay in Indonesia for a total of three months. Meanwhile, the multiple entry business visa is initially valid for 60 days. This one you can extend four times, each time by one month, hence you can stay in Indonesia for a maximum of six months.
Be aware that you are not allowed to take up employment in Indonesia, or, in any other way, make money during your stay in Indonesia using the business visa (this would be an abuse of the visa and constitutes a serious offense).
The business visa is available for those foreigners who need to visit Indonesia to conduct business negotiations or to conduct work/training assignments. With the multiple entry business visa you can enter (and leave) Indonesia various times within a one-year period. The single entry business visa only allows you to enter Indonesia once.
To obtain the business visa you will require sponsorship from an Indonesia-based company.