API (Application Programming Interface)

An API is a bridge that lets software systems talk to each other. For Generative AI, APIs allow apps or platforms to send a prompt to a model (a GPT, Claude, or Gemini) and receive the output automatically. Companies use APIs to integrate AI into existing products, for example, generating summaries inside Slack, or automating customer replies in a CRM. APIs make AI scalable and programmable rather than manually chat-based.