American expats relocating to Germany to work for an American based company are not required to obtain Visas. However, once you have entered Germany, you will have 3 months to obtain both residence and work permits in order to remain in the country for longer.
The permit process can take quite a bit of time, but temporary permits are generally issued and will be valid for 6 to 7months while you are waiting on your permanent permit.
Other requirements for staying in Germany include: being able to prove that you can support yourself financially while inthe country, and that you have health insurance at all times, while you are inGermany.
While you do not need a Visa to live and work in Germany, you do need to have a valid passport. You should make sure that your passport expiration date exceeds your scheduled departure from Germany by at least 3 months just in case you experience any delays.