Role Overview
The Principal Software Engineer leads the evolution of authentication and authorization platforms for Sezzle within a fully remote setup based in Mexico. This backend-focused position is designed for an experienced engineering leader who wants to own technical vision, architecture, and migration strategies for identity and access management. Suitable for seasoned technologists with extensive industry backgrounds, the role offers principal-level scope and ownership at a growing financial technology company.
Key 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, and modern distributed patterns.
Design and lead phased, zero-downtime migrations of auth traffic and functionality with clear rollback and safety mechanisms.
Establish and evolve authentication and authorization standards across the platform, including OAuth2/OIDC flows, token strategy, service-to-service auth, and fine-grained authorization models.
Drive consistency and scalability across a distributed microservices architecture while maintaining performance and latency budgets at the edge.
Partner with Security and Compliance to ensure the platform meets fintech-grade regulatory requirements and champion secure-by-default patterns.
Establish and evolve engineering best practices for observability, security, and CI/CD across teams with rigor on the auth-critical path.
Participate in on-call rotations, lead incident response, mentor engineers, and champion a culture of learning, innovation, and operational excellence.
Requirements
12+ years of professional software engineering experience, including significant backend experience and deployed changes to a production application in the past 30 days.
Deep, hands-on expertise in authentication and authorization systems such as OAuth2, OpenID Connect, SAML, JWT, session-based auth, and policy-as-code models.
Experience designing, building, or operating an API gateway or auth proxy at scale, whether commercial, open-source, or in-house.
Proven track record leading a large-scale service extraction or migration from a monolith to well-bounded services with minimal customer impact.
Strong proficiency in Golang with experience building and maintaining RESTful APIs.
Expertise with SQL-based relational database management systems like MySQL and PostgreSQL, including schema and query optimization.
Solid understanding of distributed systems design patterns and high-throughput, low-latency edge services.
Demonstrated ability to influence decisions and lead complex technical initiatives across multiple teams.
Demonstrated AI-forward engineering experience actively using AI tooling in development workflows.
Bachelor's degree in Computer Science or a similar technical field.
Nice to Have
Experience with identity platforms and standards implementations such as Keycloak, Auth0, Okta, Ory, or in-house identity providers.
Familiarity with service mesh and edge technologies including Envoy, Istio, mTLS, rate limiting, and WAF integration.
Familiarity with threat modeling, secure design reviews, and common authentication attack vectors.
Proficiency in observability tools such as Prometheus, Grafana, Datadog, or New Relic for latency-sensitive edge services.
Experience with AWS cloud infrastructure, specifically AWS Aurora RDS for MySQL and Postgres.
Background in fintech, payments, buy-now-pay-later, or consumer lending with familiarity in financial compliance like PCI-DSS and SOC 2.
Experience with CI/CD pipelines and containerized microservices using Docker and Kubernetes.
Skills and Tools
Languages: Golang, TypeScript, Python
Cloud and Infrastructure: AWS, Kubernetes, Docker, RDS MySQL and PostgreSQL
Tools and Platforms: Git, GitLab, API gateways, modern AI development tools
Practices: Distributed systems, microservices, zero-downtime migrations, identity and access management
Salary and Benefits
Gross monthly compensation ranging from $6,000 to $11,000 USD, negotiable based on location and experience level.
Fully remote working arrangement with no commute or relocation required.
About the Company
Sezzle aims to financially empower the next generation by transforming the shopping experience beyond payments. The company blends cutting-edge technology with seamless, interest-free installment plans that make shopping smarter and more accessible. Sezzle drives real impact on merchant sales through increased conversions and higher order values while redefining how people discover, interact with, and purchase the things they love.
How to Apply
Interested candidates should visit the official Sezzle careers page to submit an application for this remote position.
