Definition
Plain language
The well-defined set of commands one piece of software exposes for other software to call.
As stated in the literature
Application Programming Interface — a contract a system exposes for programmatic invocation, including endpoints, payload formats, and expected responses.
Also called: APIs
Why it matters: APIs are how separate software systems plug into each other, and they're the surface that AI agents act on when they 'use tools'.
For example, a weather app calls the National Weather Service API to fetch today's forecast as structured JSON.
Heard on the show
“A memory file, your calendar, your health notes, your API keys, all loaded on every single generation.”Episode 246 — 160 Perfect Refusals, And The Refusals Were The Leak