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API Security Best Practices

APIs are the backbone of modern applications—and a prime target for attackers. The OWASP API Security Top 10 provides a framework for thinking about API risks.

Authentication and Authorization

Always verify:

Authorization: Bearer <token>

Validate tokens properly:

  • Check signature
  • Verify expiration
  • Confirm audience
  • Check scopes

Rate Limiting

Prevent abuse:

X-RateLimit-Limit: 100
X-RateLimit-Remaining: 95
X-RateLimit-Reset: 1620000000

Input Validation

Never trust input:

from pydantic import BaseModel, validator

class UserInput(BaseModel):
    email: str
    age: int

    @validator('age')
    def age_must_be_positive(cls, v):
        if v < 0 or v > 150:
            raise ValueError('Invalid age')
        return v

API Gateway Security

Centralize security controls:

  • Authentication
  • Rate limiting
  • Request validation
  • Logging
  • WAF integration

Monitoring

Track anomalies:

  • Unusual request volumes
  • New client IPs
  • Error rate spikes
  • Slow response times