Germany is the major economic and political power of the European continent and a historic leader in many theoretical and technical fields.
If you would like to work in Germany, you need a residence title which permits you to work, that is a residence title for the purpose of employment.
The purposes of your stay and your training as well as your specific qualifications determine which specific residence title you qualify for:
As a highly-qualified foreigner, you may receive an open-ended residence permit immediately, subject to certain preconditions, known as a “settlement permit” (section 19 of the Residence Act). Highly-qualified foreigners are in particular scientists with special technical knowledge, as well as teaching personnel and scientific personnel in prominent positions.
As a researcher, you can receive a residence permit for research purposes in accordance with section 20 of the Residence Act
You can receive a residence permit for the purpose of self-employment if there is an economic interest or a regional need, if the activity is expected to have positive effects on the economy and the funding is secured.