API Security Checklist

Authentication and Authorization

[Critical] Implement strong authentication mechanisms (e.g., OAuth 2.0, JWT)
[High] Use HTTPS for all API endpoints
[High] Implement proper authorization checks for all API endpoints
[Medium] Use short-lived access tokens
[Medium] Implement API key rotation mechanisms

Input Validation and Sanitization

[Critical] Validate and sanitize all input data
[High] Implement proper error handling without exposing sensitive information
[High] Use parameterized queries to prevent SQL injection
[Medium] Validate content types and request payloads
[Medium] Implement proper XML/JSON parsing

Rate Limiting and Throttling

[High] Implement rate limiting to prevent abuse
[High] Use API quotas for different tiers of access
[Medium] Implement proper error responses for rate-limited requests
[Medium] Monitor and alert on unusual traffic patterns
[Low] Implement graceful degradation of service under high load

Encryption and Data Protection

[Critical] Use TLS 1.2 or higher for all API communications
[High] Implement proper key management for encryption
[High] Encrypt sensitive data at rest
[Medium] Use secure algorithms for hashing and encryption
[Medium] Implement proper certificate validation

Logging and Monitoring

[High] Implement comprehensive logging for all API requests and responses
[High] Monitor API usage patterns and alert on anomalies
[Medium] Use a centralized log management system
[Medium] Implement proper log rotation and retention policies
[Low] Conduct regular log reviews and audits

API Versioning and Documentation

[High] Implement proper API versioning
[High] Maintain up-to-date API documentation
[Medium] Use OpenAPI (Swagger) for API specification
[Medium] Implement proper deprecation policies for API versions
[Low] Provide SDKs or client libraries for common programming languages

Security Testing and Vulnerability Management

[High] Conduct regular security assessments and penetration testing
[High] Use automated API security testing tools
[Medium] Implement a vulnerability disclosure program
[Medium] Regularly update and patch all dependencies
[Low] Conduct threat modeling for API design

CORS and API Gateway

[High] Implement proper CORS (Cross-Origin Resource Sharing) policies
[High] Use an API gateway for centralized security controls
[Medium] Implement proper request validation at the API gateway level
[Medium] Use API keys for client identification
[Low] Implement API analytics and usage metrics

Note: This checklist provides a general overview of API security best practices. The specific measures you need to implement may vary depending on your API architecture, technology stack, and specific requirements. Always consult with security professionals and stay informed about the latest security trends and threats in API development.