API

An API (Application Programming Interface) is a set of rules that defines how software components talk to each other. In web development, the most common form is a REST or GraphQL API: a set of HTTP endpoints that the frontend calls to read or write data, and that third-party services expose so your app can integrate with them.

APIs are everywhere in modern software. When your app sends a message via Twilio, charges a credit card via Stripe, sends email via Resend, or stores a file in Supabase Storage — you are calling an API.

For vibe coders, APIs are the connections between your app and the rest of the internet. AI is good at writing the "glue code" to call APIs, but you still need to understand what data you are sending and what response to expect. Always check the official documentation when the AI generates an API call — hallucinated endpoint paths and parameter names are common.