Full-Stack Software Engineer II, Payments & APIs

WEX Inc.; United States; On-site; USD 96,000 - 116,000; Full time

Job summary

WEX Inc. is seeking a Full-stack Software Engineer II to contribute to the Beyond Fuel and Expense Management initiative within WEX Mobility Engineering. You will work on architecture, backend services, APIs, and partner integrations across the U.S. and India, delivering secure, scalable payment and expense solutions.

You will design and implement features spanning UI, backend, data models, and integrations, focusing on production-ready code with observability and secure development practices.

Qualifications

• Bachelor's degree in Computer Science, Software Engineering, or a related field.
• 4-6 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.
• Demonstrated ability to collaborate effectively with teammates and participate constructively in code reviews and engineering discussions.
• Hands-on experience leveraging AI coding assistants and development tools to accelerate software development, refactoring, and code generation.

Responsibilities

• Contribute to the technical design, development, and implementation of features for 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.
• Implement features 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.
• Adhere to 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 senior engineers and tech leads to identify dependencies, manage technical risks, and support delivery.
• Own technical outcomes from initial implementation through deployment, operation, and continuous improvement.

Skills

Java

Spring Boot

REST APIs

Distributed Systems

Data Modeling

AWS

CI/CD

Security

Testing

AI Coding Tools

Education

Bachelor's degree in Computer Science or related field

Master's degree in Computer Science or Software Engineering

Tools

GitHub Copilot

Cursor

Claude

OpenTelemetry

Grafana

Prometheus

Job description

WEX Inc. is seeking a Full-stack Software Engineer II to contribute to the Beyond Fuel and Expense Management initiative within WEX Mobility Engineering. You will work on architecture, backend services, APIs, and partner integrations across the U.S. and India, delivering secure, scalable payment and expense solutions.

You will design and implement features spanning UI, backend, data models, and integrations, focusing on production-ready code with observability and secure development practices.