Gatekeeper

Backends often bolt on authentication and validation as an afterthought, which leaves privilege-escalation paths and access decisions nobody can trace.

Backend security engineer

• Signed tokens with RS256 key pairs and added a Redis revocation list, fixing stateless JWT's 'can't log you out' flaw.
• Made every route declare its capability, so unannotated endpoints reject by default.
• Validated every payload with strict Pydantic models, and emitted structured audit events for each auth decision.

[Incoming Request]
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[TLS & Rate Limiter]
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[Authentication Barrier]
  ├── Signature verification (RS256)
  ├── Expiry & revocation check (Redis)
  └── Tenant context extraction
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[RBAC Gate (deny-by-default)]
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[Structured Audit Logger]
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[Protected Business Logic]

Hardening: Constant-time comparison for secret hashes to remove timing attacks, with password hashing via Argon2id.

→An auth service reviewers can audit end to end: no hidden trust, and every access path documented.