Why API Security Matters

APIs power most modern applications, connecting mobile apps, web front-ends, and third-party integrations. Because they are often directly reachable over the internet, weaknesses can expose significant amounts of data.

Common API Risk Areas

  • Broken authentication — insufficient verification of API callers.
  • Excessive data exposure — returning more data than a client actually needs.
  • Lack of rate limiting — allowing unrestricted, automated requests.
  • Broken object-level authorization — failing to verify a user can only access their own resources.
conceptual — authorization check 
// Always verify the caller owns the requested resource
if (resource.ownerId !== currentUser.id) { deny(); }

Defensive Practices

  1. Require strong authentication (such as OAuth 2.0) for all API endpoints.
  2. Enforce authorization checks on every request, not just at login.
  3. Apply rate limiting and monitoring to detect abuse.
  4. Return only the minimum data fields necessary for each response.
  5. Use HTTPS for all API traffic without exception.