In addition to acting as the army for their country, the ninja village also acts as a business. Each day clients will come to the village and pay for the services of the ninja. These jobs can range from the mundane (walk the feudal lord's dog), to the assassination of deadly wanted criminals. As needed the Kage or Jounin master of a Genin team can assign missions in furtherance of a duty to the country that are unpaid.

These jobs are thus divided into difficulty ranks of S, A, B, C and D and then given to ninja based on their ability. If the mission is completed successfully, the client will then pay the village. The easiest and least deadly jobs are given to the Genin, these are called "D-Rank". The D-Rank missions also help to build teamwork skills among the new Ninja Academy graduates. D-Rank are therefore non-combat with low pay. The "C-Rank" missions will be given to Chuunin and skilled Genin. These include protective escorts and missions with some chance of bodily harm. It can include capturing wild animals and mine clearing. "B-Rank" missions will be given to Special Jounin and Chuunin. These also include protective escort, gathering foreign intelligence and killing of ninja. Open battle is generally not an issue during this mission type. The next highest rank missions, "A-Rank" are given to Jounin and Special Jounin. These include vital missions between nations, escorting VIPs and maneuvers against offensive ninja forces. Thus these missions will almost always involve combat and risk of death. At the highest and most dangerous is "S-rank", given to Jounin. These missions include assassination of important persons, transporting classified documents and materials. With the extreme danger comes a very high rate of pay.

Rank D Mission: The lowest missions. Physical labour, finding lost animals or items of little value, among other things, usually taken inside the village. Fit for Genins.

Rank C Mission: Little higher than D's. Escorting people or finding lost stuff in other places than in the village are usually C rank missions. Chuunins usually take this, although a lot of Genins do these as well.

Rank B Mission: These ones start to get dangerous. Defending someone or something, carrying important stuff or assassination of weak or unprotected persons are missions of this rank. Jounins and sometimes Chuunins usually take this kind of missions.

Rank A Mission: Highly dangerous missions. Invasion, protecting the village against invasions, assassination of powerful people and such, are A rank. Anbu squad members or other powerful Jounins or Sannins usually take these missions.

Rank S Missions: The higher rank of difficulty. These missions tend to be urgent missions of great danger or world importance matters or even Top Secret Village stuff. Kages tend to do these, although a lot of other powerful ninjas may be assigned to this.