• Argon2id password hashing
• Password-complexity and minimum-length validation
• Generic password-recovery and verification responses
• Temporary lockout after repeated failed logins
• JWT issuer, expiry, type and required-claim validation
• Short access-token lifetime
• Rotating refresh tokens stored as JTI hashes
• Refresh-token family revocation after reuse detection
• Per-session and global session revocation
• Encrypted TOTP secrets using Fernet with a derived encryption key
• Hashed single-use backup codes
• API keys returned once and stored only as SHA-256 hashes
• API-key scope intersection with the owning user's permissions
• Hashed one-time verification, reset, invitation and email-change tokens
• Role and permission checks on privileged routes
• Organization role enforcement for tenant operations
• Audit records containing actor, action, outcome, request ID, IP and user agent
• Request IDs and defensive response headers
• Redis-backed rate limiting with local fallback
• Soft deletion and session revocation for deleted or disabled accounts

1. Store signing and encryption secrets in a managed secrets service.
2. Use long, independent, randomly generated secrets and rotate them safely.
3. Disable EXPOSE_DEBUG_TOKENS and DEBUG.
4. Require HTTPS at the ingress and use secure network policies.
5. Configure a real SMTP or transactional-email provider.
6. Restrict CORS origins and trusted hosts.
7. Use PostgreSQL with encrypted backups and tested restore procedures.
8. Centralize audit logs in append-only or tamper-evident storage.
9. Add metrics, anomaly alerts and security incident runbooks.
10. Perform SAST, dependency scanning, DAST and penetration testing.

Every login creates a token family. Refreshing revokes the current token and issues its replacement in the same family. Presenting an already-rotated token is treated as potential theft and revokes every active token in that family.

The TOTP seed is encrypted before database storage. The encryption key is derived from ENCRYPTION_SECRET. In a high-assurance deployment, replace this with envelope encryption through a KMS or HSM.

Do not disclose sensitive vulnerabilities publicly. Share a minimal reproduction privately with the system owner, including the affected route, impact and recommended remediation.