Senior Full-Stack Engineer (Java / Spring Boot)

This is a remote position; however, the candidate must reside within 30 miles of one of the following locations: Boston, MA; San Francisco Bay Area, CA; Dallas, TX; Salt Lake City, UT; Seattle, WA; and Portland, MEAbout the Team/RoleWe are seeking a Full-stack Senior Software Engineer with deep expertise in backend development to contribute to the WEX Beyond Fuel and Expense Management initiative within WEX Mobility Engineering.This is a brand-new initiative, offering the opportunity to shape the architecture, establish engineering practices, and build the product from initial design through production launch. You will work across web & mobile applications, backend services, APIs, and partner integrations to deliver secure, reliable, and scalable payment and expense management experiences. This is an individual contributor role focused on delivering core capabilities while collaborating with Product, Design, Security, and engineering teams across the United States and India.​How you’ll make an impact:Contribute to the technical architecture, design, and implementation of the Beyond Fuel and Expense Management platform.Build full-stack capabilities spanning user interfaces, backend services, data models, and external integrations.Translate product requirements into technical designs, delivery milestones, and implementation plans.Design reusable business capabilities and APIs that support web, mobile, and partner experiences.Establish patterns for payment workflows, expense capture, approvals, spend controls, transaction reporting, and reconciliation.Evaluate technical options and communicate tradeoffs involving performance, security, reliability, cost, and delivery timelines.Write production code, review contributions, and resolve complex issues across the application stack.Participate in design reviews, code reviews, and technical discussions to support engineering quality.Establish standards for automated testing, API contracts, observability, accessibility, and secure development.Build production readiness into the product through actionable logs, distributed tracing, metrics, dashboards, and alerts.Use approved AI tools throughout development, testing, and documentation, and review and validate all generated output.Partner with engineering leaders to identify dependencies, manage technical risks, and support delivery.Own technical outcomes from initial implementation through deployment, operation, and continuous improvement.Experience you'll bring:Bachelor's degree in Computer Science, Software Engineering, or a related field.6–8 years of professional software engineering experience.Strong proficiency in Java and Spring Boot, or comparable backend technologies.Strong understanding of object-oriented design, data structures, algorithms, and software design principles.Experience designing REST APIs, distributed systems, relational data models, and event-driven integrations.Experience with cloud platforms, preferably AWS, and automated CI/CD pipelines.Knowledge of authentication, authorization, data protection, and secure API design.Experience with unit, integration, end-to-end, and performance testing.Experience building and operating production services with monitoring, distributed tracing, and incident troubleshooting.Strong communication skills to collaborate effectively across multidisciplinary teams.Ability to explain technical decisions clearly to engineering and business stakeholders.A track record of mentoring engineers and improving engineering practices through hands-on collaboration.Hands-on experience leveraging AI coding assistants and development tools (e.g., GitHub Copilot, Cursor, Claude) to accelerate software development, refactoring, and code generation. Preferred Qualifications:Master's degree in Computer Science or Software Engineering.8+ years of software engineering experience.Experience with API Gateways, service mesh technologies, and cloud networking concepts.Familiarity with OpenTelemetry, Grafana, Prometheus, or similar observability platforms.Exposure to web and mobile application developmentThe base pay range represents the anticipated low and high end of the pay range for this position. Actual pay rates will vary and will be based on various factors, such as your qualifications, skills, competencies, and proficiency for the role. Base pay is one component of WEX's total compensation package. Most sales positions are eligible for commission under the terms of an applicable plan. Non-sales roles are typically eligible for a quarterly or annual bonus based on their role and applicable plan. WEX's comprehensive and market competitive benefits are designed to support your personal and professional well-being. Benefits include health, dental and vision insurances, retirement savings plan, paid time off, health savings account, flexible spending accounts, life insurance, disability insurance, tuition reimbursement, and more. For more information, check out the "About Us" section.Pay Range: $121,500.00 - $145,500.00SummaryLocation: Portland, ME; US - Remote; Seattle, WA; San Francisco, CA; Boston, MA; Salt Lake City, UT; Dallas, TXType: Full time