What is an HTTP API?

An HTTP API exposes backend functionality through HTTP endpoints. Clients send HTTP requests (often with JSON) and receive HTTP responses (often JSON).

Core pieces

  • Endpoint: e.g., /users, /orders/123
  • Methods: GET (read), POST (create), PUT/PATCH (update), DELETE (remove)
  • Headers: e.g., Content-Type, Authorization
  • Body: usually JSON for write operations
  • Status codes: 200/201/400/401/403/404/500

HTTP vs HTTPS

HTTPS = HTTP + TLS encryption (what you should use in real systems).

How “keys” show up in HTTP APIs

  • API keys
  • Bearer tokens / JWT
  • OAuth2
  • HMAC request signatures

REST API = a design style/standard for some HTTP APIs (how you structure endpoints, methods, resources, status codes, statelessness).