Senior .NET Authentication Developer

The Role

We’re looking for a Senior .NET Developer to own and lead our production authentication microservice. This system powers JWT tokens, MFA, RBAC, and enterprise security for our entire platform. You will be the sole technical owner, collaborating with IT for Azure infrastructure, and making security-first architectural decisions.

Tech Stack

• Backend: .NET 8, C# 12, ASP.NET Core Web API
• Database: PostgreSQL (via Entity Framework Core)
• Caching & Auth: Redis, JWT
• Infrastructure: Azure Container Apps, Docker
• Scale: 20k+ LOC, 25+ DB entities

Key Responsibilities

• System Maintenance & Security (40%)
• Maintain 99.9% uptime for authentication services
• Investigate and resolve security incidents
• Optimize DB queries & caching for authentication flows
• Review audit logs and enforce security hardening
• Feature Development (35%)
• Build new authentication endpoints
• Enhance MFA & RBAC capabilities
• Integrate with new microservices and frontends
• Add compliance-driven security features
• Architecture & Leadership (25%)
• Maintain clean architecture & repository patterns
• Lead database schema evolution
• Write comprehensive technical documentation
• Mentor team members on security best practices

Required Skills

• Authentication & Security (Primary):
• 3+ years in production authentication systems (JWT, OAuth, SSO, MFA)
• Enterprise RBAC implementation with tenant isolation
• Multi-factor authentication (TOTP, SMS/Email OTP, backup codes)
• Security incident investigation & breach response
• Password security (BCrypt, breach detection)
• Audit logging & compliance reporting
• .NET Development:
• 6+ years in C# 8+, ASP.NET Core
• Entity Framework Core (complex queries, performance tuning)
• Repository pattern, clean architecture, async/await
• RESTful API design & versioning
• Database & Performance:
• PostgreSQL: advanced SQL, indexing, optimization
• Redis: distributed caching, session/token storage
• Multi-tenant schema design & scaling
• DevOps:
• Docker multi-stage builds
• Azure services: Container Apps, Key Vault, Application Insights
• CI/CD pipelines & automated testing

Ideal Candidate

Deep expertise in authentication protocols & enterprise security patterns, proven success in multi-tenant SaaS authentication systems, security-first approach to architecture, and strong production debugging skills.

Minimum Qualifications

• 3+ years in production authentication (JWT, OAuth, MFA, SSO)
• Experience with RBAC, password policies, audit logging, incident response
• Hands-on architecture & implementation of multi-tenant authentication systems