API security best practices in 2025
APIs are the backbone of modern applications—and increasingly the primary attack surface. According to Salt Security's State of API Security Report, API attacks increased 681% in 2024, with 94% of organizations experiencing API security incidents. As APIs proliferate, security must evolve from an afterthought to a foundational design principle.
The API security landscape in 2025
According to Akamai's State of the Internet Report, web attacks targeting APIs grew faster than any other attack category, with credential stuffing and broken authentication leading the threat landscape.
OWASP API Security Top 10 (2023)
Broken Object Level Authorization
APIs exposing endpoints that handle object identifiers, creating a wide attack surface.
Broken Authentication
Flaws in authentication mechanisms allowing attackers to compromise tokens or exploit implementation flaws.
Broken Object Property Level Authorization
Lack of or improper authorization validation at object property level.
Unrestricted Resource Consumption
API requests consuming excessive resources without proper limits.
Broken Function Level Authorization
Complex access control policies with unclear separation between admin and regular functions.
Critical Vulnerability: Broken Object Level Authorization (BOLA) accounts for 40% of API attacks. This occurs when APIs don't verify that the requesting user has permission to access the specific object being requested.
Attack vectors and threats
API Attack Distribution by Type (2025)
Authentication best practices
OAuth 2.0 + OIDC
Industry standard for delegated authorization with identity verification
JWT Best Practices
Short expiration, secure signing algorithms, proper validation
API Keys + Secrets
For server-to-server communication with proper rotation
mTLS
Mutual TLS for high-security service mesh communication
Multi-Factor Auth
Additional verification for sensitive operations
Token Binding
Bind tokens to specific clients to prevent theft
Zero Trust API architecture
Zero Trust vs Traditional API Security
| Feature | Zero Trust Model | Traditional Perimeter |
|---|---|---|
| Verify Every Request | ✓ | ✗ |
| Least Privilege Access | ✓ | ✗ |
| Microsegmentation | ✓ | ✗ |
| Continuous Validation | ✓ | ✗ |
| Encrypted Communications | ✓ | ✓ |
| Context-Aware Decisions | ✓ | ✗ |
Zero Trust Principle: Never trust, always verify. Every API request should be authenticated and authorized regardless of where it originates—internal or external.
Rate limiting and throttling strategies
Rate Limiting Strategy Effectiveness (%)
Input validation and sanitization
Schema Validation
Enforce strict OpenAPI/JSON schema at gateway level
Type Checking
Validate data types, lengths, formats before processing
Sanitization
Clean input to prevent injection attacks
Content Validation
Verify content-type headers match body content
Business Rules
Apply domain-specific validation logic
Output Encoding
Properly encode output to prevent XSS
API gateway security features
Traffic Management
Rate limiting, throttling, load balancing, request routing.
Authentication
OAuth validation, API key verification, JWT parsing.
Authorization
Policy enforcement, scope validation, RBAC/ABAC.
Threat Protection
WAF rules, bot detection, DDoS mitigation, injection prevention.
Observability
Logging, metrics, tracing, anomaly detection.
Secrets management
Secrets Management Solutions Comparison
| Feature | HashiCorp Vault | AWS Secrets Manager | Azure Key Vault | GCP Secret Manager |
|---|---|---|---|---|
| Dynamic Secrets | ✓ | ✓ | ✗ | ✗ |
| Auto-Rotation | ✓ | ✓ | ✓ | ✓ |
| Audit Logging | ✓ | ✓ | ✓ | ✓ |
| K8s Integration | ✓ | ✓ | ✓ | ✓ |
| Cloud Native | ✓ | ✓ | ✓ | ✓ |
| Open Source | ✓ | ✗ | ✗ | ✗ |
Security testing approaches
API Security Testing Coverage (%)
DevSecOps integration
Design Phase
Threat modeling, security requirements, API design review
Development
Secure coding standards, IDE security plugins, pre-commit hooks
CI Pipeline
SAST scanning, dependency checks, secrets detection
CD Pipeline
DAST testing, container scanning, config validation
Production
Runtime protection, monitoring, incident response
Continuous
Vulnerability management, penetration testing, audits
Shift Left: Organizations that integrate security testing early in the development lifecycle reduce vulnerability remediation costs by 10x compared to finding issues in production.
API security monitoring
API Attack Volume Trend (Sample Enterprise)
Implementation checklist
FAQ
Q: Should we use API keys or OAuth for authentication? A: Use OAuth 2.0 for user-facing applications and delegated access. API keys are appropriate for server-to-server communication where you control both ends. Never use API keys alone for user authentication.
Q: How often should we rotate API credentials? A: Rotate API keys at least quarterly, OAuth client secrets annually, and implement automatic rotation for database credentials. Use short-lived tokens (15 minutes to 1 hour) wherever possible.
Q: What's the best way to handle API versioning securely? A: Maintain security patches for all supported versions, clearly communicate deprecation timelines, and ensure legacy versions don't bypass newer security controls.
Q: How do we secure internal APIs? A: Apply the same zero trust principles as external APIs. Use service mesh for mTLS, implement proper authentication between services, and monitor internal API traffic for anomalies.
Sources and further reading
- OWASP API Security Top 10
- Salt Security State of API Security
- Akamai State of the Internet
- NIST API Security Guidelines
- Google API Security Best Practices
Secure Your APIs: API security requires expertise across authentication, authorization, and threat detection. Our team helps organizations design and implement comprehensive API security strategies. Contact us to discuss your API security needs.
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