Enterprise APIs are high-value attack targets. They expose business logic, sensitive data, and system integrations that internal applications depend on. A compromised API can result in data breaches, regulatory penalties, and significant reputational damage. Security cannot be an afterthought in API design.
This article covers the security patterns GROW TECH INFO implements in production REST and GraphQL APIs for enterprise clients.
Authentication: Beyond Basic Tokens
JWT (JSON Web Tokens) are widely adopted but frequently misimplemented. Common mistakes include: using symmetric secrets that are too short, not validating the `aud` and `iss` claims, allowing algorithm negotiation from the client, and setting excessively long expiry times.
For enterprise APIs, implement short-lived access tokens (15 minutes) with refresh token rotation. Store refresh tokens in HTTP-only, SameSite=Strict cookies — not localStorage. Implement token revocation with a Redis-backed denylist for logout and suspicious activity responses.
OAuth 2.0 with PKCE is the correct pattern for APIs consumed by third-party clients. Do not build custom authentication flows when OAuth handles delegation securely.
Authorization: Principle of Least Privilege
Authentication confirms identity; authorization determines what that identity can do. Implement Role-Based Access Control (RBAC) at the middleware layer, not within individual endpoint handlers. A missed authorization check in one handler should not expose data.
For complex permission models, consider Attribute-Based Access Control (ABAC), where authorization decisions consider the resource attributes, user context, and environmental conditions simultaneously. Libraries like Casbin implement ABAC/RBAC with policy file definitions.
Input Validation and Injection Prevention
Every API input is a potential attack vector. Validate all incoming data against strict schemas before it touches business logic or database queries. Use libraries like Zod (TypeScript) or Pydantic (Python) for runtime schema validation.
Never concatenate user input into SQL queries. Use parameterized queries or ORM query builders exclusively. For GraphQL APIs, implement query depth limiting and query complexity analysis to prevent denial-of-service through deeply nested queries.
Rate Limiting and DDoS Protection
Implement rate limiting at multiple levels: per-IP for anonymous requests, per-user for authenticated requests, and per-API-key for third-party integrations. Exponential backoff windows prevent brute-force attacks on auth endpoints.
Deploy API gateways (AWS API Gateway, Kong, Nginx) in front of your application servers to offload rate limiting, SSL termination, and request logging from application code. This architectural separation provides defense in depth.
Secrets Management
Hardcoded credentials in source code are still one of the most common vulnerabilities found in security audits. Use secret management services (AWS Secrets Manager, HashiCorp Vault, Azure Key Vault) for all credentials. Rotate secrets programmatically and audit access logs.