API is the English abbreviation of the American Petroleum Institute. Built in 1919, it was the first national commercial association in the United States and one of the earliest and most successful chambers of the world to set standards.

An important task of the API is to standardize the equipment used in the oil and gas industry to ensure the safety, reliability and interchangeability of equipment used in industry. Establishing harmonized standards is one of the earliest and most successful projects of the API. Since the release of the first standard in 1924, up until now, the API has released more than 500 standards. The API is an ANSI-approved standard setting body. Its standards development follows ANSI's guidelines for coordination and development procedures. The API also develops and publishes standards in conjunction with ASTM. In addition, API actively participates in the formulation of ISO standards that are suitable for global industries. It is the secretariat of ISO/TC671SC9 wellhead equipment and pipeline valves.

API standards are widely used and not only cited by U.S. domestic companies, U.S. federal and state laws and regulations, as well as by government agencies such as the Department of Defense, U.S. Customs, Environmental Protection Agency, U.S. Geological Survey, etc., but also internationally and internationally More than 100 national standards cited.

API standards primarily specify equipment performance, sometimes including design and process specifications. The areas of standards development include oil production, oil refining, measurement, transportation, sales, and environmental regulations. Its information technology standards include EDI, communications and information technology applications in the oil and gas industry.

API enjoys high prestige both in the United States and in other countries in the world. It is a petroleum machinery certification body recognized by the U.S. Department of Commerce and the U.S. Trade Commission. Its technical standards for petrochemical and oil extraction machinery are adopted by many countries. Oil companies in many countries in the Middle East, South America, and Asia are generally required to participate in bidding products with the API mark when they bid for petroleum machinery. Today, APIs are increasingly becoming an integral part of petroleum industry activities not only in the United States but also in the world.