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API
API Contract
Client asks. API responds. Your UI updates.
Treat security as part of API design, not a final patch.

Why API Security Comes First

APIs expose business logic and data. Security defines who can call what, how requests are trusted, and how abuse is prevented.

Basic Authentication

Basic Auth sends `username:password` encoded in base64 in every request. It is simple, but should only be used over HTTPS and for limited cases.

Token / Bearer Authentication

Clients send a token (often JWT or opaque token) in the Authorization header. This is common for mobile/web session APIs.

OAuth 2.0 for Delegated Access

OAuth 2.0 lets users grant apps scoped access without sharing passwords. Typical flow: authorize -> code -> token exchange.

Scopes and Roles

A valid token is not enough. Enforce scopes/roles per endpoint so tokens only access allowed operations.

Token Expiry and Rotation

Short-lived access tokens reduce risk. Refresh tokens rotate sessions safely without forcing frequent logins.

Defense in Depth

Combine auth with rate limits, IP allowlists, request signing, audit logs, and HTTPS everywhere for stronger API security posture.

API Security Fundamentals Ready

You can now choose and implement auth patterns like Basic Auth, Bearer tokens, and OAuth 2.0 with production-grade safeguards.

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