API (disambiguation)
- AP1 (disambiguation)
- API
- API Network
- API gravity
- API number
- API oil-water separator
- Academic Performance Index
- Academic Programs International
- Active pharmaceutical ingredient
- Air Pollution Index
- Aliansi Perempuan Indonesia
- Alliance for Italy
- American Petroleum Institute
- Aminopropylindole
- Analytical Profile Index
- Animal Protection Institute
- Anonima Petroli Italiana
- Api (apple)
- Api (mountain)
- Api Chamber
- Apnea–hypopnea index
- Arab Peace Initiative
- Armor-piercing incendiary
- Asian-Pacific Islander
- Associated Producers Incorporated
- Athletes' Performance Institute
- Atmospheric pressure ionization
- Auburn University
- Australian Pharmaceutical Industries
- Australian Property Institute
- Automated Processes, Inc.
- Automobile Products of India
- Aviation Partners Inc.
- International Phonetic Alphabet
- List of pharmaceutical companies
- Mount Api
- United States Naval Aviator