Principal Backend Engineer - Auth & Platform (Remote)

Sezzle LA; United States; Remote; USD 6,000 - 11,000; Full time

Benefits offered by this job

Fully remote

Job summary

Sezzle is seeking a Principal Software Engineer to own authentication and authorization evolution across the platform. This backend-focused role will define the technical vision, architecture, and migration strategy for a scalable API gateway and identity services.

You will design, develop, and lead zero-downtime migrations, ensure fintech-grade security, and mentor engineers while collaborating with product, security and compliance teams. This fully remote role offers global impact.

Qualifications

• 12+ years of professional software engineering experience, including significant backend experience.
• Experience deploying changes to a production application in the past 30 days.
• Deep, hands-on expertise in authentication and authorization systems: OAuth2, OpenID Connect, SAML, JWT and session-based auth, token lifecycle management, and modern authorization patterns (RBAC, ABAC, policy-as-code).
• Experience designing, building, or operating an API gateway or auth proxy at scale: Kong, Envoy, AWS API Gateway, Traefik, or in-house edge service.
• Proven track record leading a large-scale service extraction or migration with minimal customer impact.
• Bachelor’s degree in Computer Science or a related field.

Responsibilities

• Own the technical vision and roadmap for Sezzle’s authentication and authorization platform, including a dedicated API auth gateway and supporting identity services.
• Architect, design, and build scalable, highly-available auth services and gateway components primarily in Golang, leveraging AWS, RDS (MySQL/Postgres), and modern distributed patterns.
• Design and lead phased, zero-downtime migrations of auth traffic and functionality, with clear rollback and safety mechanisms at every step.
• Establish and evolve authentication and authorization standards across the platform: OAuth2/OIDC flows, token strategy (JWT, opaque, refresh), service-to-service auth (mTLS, workload identity), and fine-grained authorization models (RBAC/ABAC/policy engines).
• Drive consistency and scalability across a distributed microservices architecture while maintaining the performance, reliability, and latency budgets expected of an edge gateway.
• Partner with Security and Compliance to ensure the new platform meets fintech-grade security and regulatory requirements, and champion secure-by-default patterns across engineering.
• Establish and evolve engineering best practices for observability, security, and CI/CD across teams, with particular rigor on the auth-critical path.
• Participate in the on-call rotation for the services you own, and help lead incident response and postmortems on the auth-critical path.
• Mentor engineers and champion a culture of learning, innovation, and operational excellence.
• Collaborate cross-functionally to translate business goals into technical roadmaps and deliver results that matter.

Skills

Backend engineering

Authentication & Authorization

Golang

API gateway / auth proxy

SQL (MySQL / PostgreSQL)

Distributed systems

AI tooling

Leadership / mentoring

Education

Bachelor's degree in Computer Science or similar

Tools

Kong

Envoy

AWS

Docker

Kubernetes

MySQL

PostgreSQL

Job description

Sezzle is seeking a Principal Software Engineer to own authentication and authorization evolution across the platform. This backend-focused role will define the technical vision, architecture, and migration strategy for a scalable API gateway and identity services.

You will design, develop, and lead zero-downtime migrations, ensure fintech-grade security, and mentor engineers while collaborating with product, security and compliance teams. This fully remote role offers global impact.