Identity is the new perimeter. Learn to harden the digital gates of your infrastructure and implement tamper-proof authentication mechanisms using JWT and OAuth2.
An API Gateway acts as the single entry point for all clients. It is the fortress gate. If the gateway fails, the backend microservices are exposed directly to the open internet.
The Gateway is responsible for cross-cutting concerns that shouldn't be handled by individual services:
Rate limiting and throttling to prevent Denial of Service (DoS) and brute-force attacks.
Validating headers, checking for SQL injection patterns, and enforcing SSL/TLS termination.
Authentication (AuthN) verifies who you are. Authorization (AuthZ) verifies what you can do. In modern REST APIs, we typically use Stateless Authentication via JSON Web Tokens (JWT).
Critical Risk: If the signing key is weak or leaked, attackers can forge tokens with
"role": "admin" privileges.
According to the OWASP API Security Top 10, broken object level authorization (BOLA) is the most critical vulnerability.
User A changes the ID in a URL (e.g., /orders/55 -> /orders/56) and
views User B's data because the backend didn't verify ownership.
The API returns the full user object (including password hash or address) to the frontend, relying on the client to filter it out.
To secure high-performance Node.js systems, we must adopt a "Zero Trust" mindset regarding identity.
Confidential documents for further study: