I will design and build a secure oauth or sso authentication systems

Are you building a login system, SSO, or secure API authorization and need it done right?

I'm a senior backend engineer who built OAuth 2.0 authorization server from scratch serving 60M+ daily active users implementing RFC 6749 and RFC 9068 with zero downtime migration, Redis cluster architecture, and zero user impact.

What I can build for you:

OAuth 2.0 authorization server (authorization code, client credentials, refresh token flows)

JWT / opaque token issuance and validation

SSO integration (Google, GitHub, custom OIDC providers)

Spring Security or Node.js auth middleware

IAM policy engines and role-based access control (RBAC)

Token migration with zero downtime

Secure API gateway authentication

Tech stack: Java / Spring Boot, Spring Security, Node.js, Redis, JWT, OAuth 2.0, OIDC

Who this is for:

Startups needing a secure auth layer, SaaS products adding SSO, or teams with broken/insecure authentication they need fixed fast.

I've done this at fintech scale. I'll deliver clean, production-ready code with documentation.

Message me before ordering to discuss your use case I'll tell you exactly what's needed.