What should I use to protect APIs from abuse and attacks?

To protect APIs from abuse and attacks, use a layered approach rather than a single tool.

Core protections

• Authentication: Verify who is calling the API
  • OAuth 2.0 / OpenID Connect, API keys, mTLS for service-to-service
• Authorization: Verify what they’re allowed to do
  • RBAC/ABAC, scoped tokens, least privilege
• Rate limiting / throttling: Prevent brute force and flooding
  • Per user, per token, per IP, per endpoint
• Input validation: Block malformed or malicious payloads
  • Schema validation, allowlists, size limits
• WAF / API gateway: Filter common attacks and centralize controls
  • Helps against injection, bot traffic, and request anomalies
• Logging and monitoring: Detect abuse early
  • Alert on spikes, auth failures, unusual geographies, or patterns
• TLS everywhere: Protect data in transit
• Secrets management: Keep keys and credentials out of code
• CORS and CSRF controls: Especially for browser-accessed APIs
• Versioning and deprecation: Reduce exposure from old, vulnerable endpoints

Common attack-specific defenses

• Brute force / credential stuffing: rate limiting, MFA, bot detection
• Injection attacks: parameterized queries, strict validation, WAF
• DoS / DDoS: CDN, edge protection, request caps, autoscaling
• Broken object-level auth (BOLA/IDOR): object-level authorization checks
• Replay attacks: timestamps, nonces, short-lived tokens
• Enumeration: generic error messages, response shaping

Best practical setup

A strong baseline is:

1. API gateway
2. OAuth/OIDC or signed service tokens
3. Per-client rate limiting
4. Strict schema validation
5. Centralized logging/alerting
6. WAF/CDN in front of public endpoints

If you want, I can recommend a specific stack for AWS, Azure, GCP, or Kubernetes.