Who Can Get a Job in Germany?
Citizen of any country can apply for a job in Germany but some nationals will have it more difficult than others to get it. This has to do with German foreign labour regulations.

Who Needs a Work Permit in Germany?
In general, citizens of countries from outside of the European Economic Area (EU and EFTA) need a work permit (that is a residence permit for gainful employment) to be allowed to work in Germany. Thus, as you may assume, there are two categories of foreign job seekers in Germany, those from the EEA and those from outside the EEA:

EU/EEA Citizens
Nationals of the European Economic Area (EEA), which includes the EU and EFTA countries, have an unrestricted access to the German labour market and will be treated the same way as any German national when applying for a job in Germany. They do not need a work or residence permit and their employers do not have to prove to the German labour authorities that the position could not have been filled by a German citizen.

Citizens of Third Countries
Foreigners coming from countries outside of the EEA need a residence permit for work purposes (also called residence permit for gainful employment) whereas in order to get this permit their employer must usually prove that there were no suitable candidates for the job amongst applicants from the EEA countries. This applies to all non-EEA nationals, irrespective of whether they need a visa to enter Germany or not.

However, exceptions do exist when it is not necessary to prove that there are no suitable candidates from within the EEA. For example, citizens of third countries who have earned their university degree in Germany can stay in the country for another 18 months while looking for a job. Once they have found a job that corresponds to their qualifications, they can convert their residence permit for study purposes into a residence permit for gainful employment. In addition, foreign graduates of German universities who left home after completing their studies can still return to Germany for job hunting.

Likewise, foreigners from third countries who have completed a vocational training in Germany can have their residence permit extended for another 12 months to find a job that suits their qualifications. During this 12 month period they can take up any job to help cover their living costs in Germany until they find a work they were originally trained for.

Another exception are highly skilled individuals having a binding offer for any specialist job that pays them at least 52,000 Euros a year (applies to 2018). Also, there is an exception for certain specialist professions where there is a chronic lack of suitable candidates from within the EEA provided that the candidate has been offered an annual salary of no less than 40,560 Euros. These jobs include doctors of medicine as well as the so-called MINT professions (mathematics, informatics, natural sciences and technology/engineering). All those mentioned in this paragraph are eligible for the EU Blue Card (temporary residence title).

In addition, the Federal Employment Agency has whitelisted jobs with vocational training where shortages exist that are also available to applicants from non-EEA countries.