[Remote] Sr. Software Engineer (AI & Backend)

Note: The job is a remote job and is open to candidates in USA. WEX is a company that provides fleet management and mobility payment solutions. They are seeking a seasoned Sr. Software Engineer to design, develop, and maintain robust backend services and APIs while collaborating with cross-functional teams to implement new features.ResponsibilitiesDesign, develop, and maintain robust, scalable, and high-performance object oriented code in our backend servicesDevelop public REST APIs using Java and internal gRPC APIs for inter-service and inter-system communicationCraft systems designs, lead design decisions, and drive alignment with other senior engineersWrite automated unit tests, integration tests, end-to-end tests, concurrency tests, load/performance testsAnalyze existing systems to identify bottlenecks, tech debt, and implement scalability, and stability improvementsImplement automation for testing, monitoring, healing, and scaling applications, continuous integration and deployment to reduce time to marketCollaborate with cross-functional teams, including product managers, designers, and other engineers, to define and implement new featuresConduct code reviews (comment, approve, seek revisions, merge), mentor junior and mid-level engineers, and actively promote engineering best practicesDive deep and troubleshoot complex issues, devise fixes, author root cause analysis documents, and ensure lasting performance and reliabilityConduct objective and comparative analyses of competing technologies to advise the team of pros and cons of a technology solutionMaintain robust documentation (design docs, run books, change management docs, and readiness plans)Provide live-site support for production applications by monitoring systems, ensuring rapid incident resolution, and driving continuous improvementDrive cross-team projects as a single-threaded-owner (STO) or tech lead, and actively unblock other engineers to make progressSkillsBachelor's degree in Computer Science or Software Engineering8 years of professional experience in software engineeringStrong understanding of data structures and algorithms, object-oriented design, and problem-solving skillsExpertise in designing and developing internet-scale services with scalability, availability, security, and reliability design tenetsExcellent written and verbal communication skills, and a collaborative and empathetic mindsetProficiency in backend development, with proficiency expertise in Java or C#, and frameworks like SpringBoot, building and optimizing RESTful APIs, ODATA framework, and SQLExperience in leveraging AI-enabled development tools such as Cursor AI, Kiro and GitHub Copilot to accelerate feature delivery, automate documentation, and enhance code qualityMaster's degree in computer science or software engineering8 years of experience in software engineeringExperience with event-driven architecture and tools like KafkaExperience working on card paymentsFamiliarity with cloud-native architecture (containerization using tools such as Docker and Kubernetes)Experience building AI skills & deploying AI solutions to production environmentsExperience building production-grade AI agents or copilotsFamiliarity with multi-agent systems and distributed AI architecturesExperience with vector databases (e.g., Pinecone, Weaviate, OpenSearch, Milvus)Knowledge of AI evaluation techniques, safety practices, and responsible AI principlesBenefitsCommission under the terms of an applicable plan for sales positionsQuarterly or annual bonus based on their role and applicable plan for non-sales rolesHealth, dental and vision insurancesRetirement savings planPaid time offHealth savings accountFlexible spending accountsLife insuranceDisability insuranceTuition reimbursementCompany OverviewWex is a financial technology service provider for fleet, travel and healthcare industries. It was founded in 1983, and is headquartered in Portland, Maine, USA, with a workforce of 5001-10000 employees. Its website is http://www.wexinc.com.Company H1B SponsorshipWEX has a track record of offering H1B sponsorships, with 4 in 2026, 22 in 2025, 10 in 2024, 12 in 2023, 20 in 2022, 14 in 2021, 18 in 2020. Please note that this does not guarantee sponsorship for this specific role.