SDE 3 - Backend

We are seeking a seasoned Sr Software Engineer in the WEX Mobility Engineering organisation. This role will sit in the North America Mobility team that caters to fleet management and mobility payments solutions to our large customers and partners in the North America region. The mobility development team spans across the USA, Brazil, and India. Our mobility systems provide SaaS and API solutions to various customers. WEX Mobility products enable credit issuance to fleet companies and their workers in the form of WEX or co-branded credit cards, usable at fuelling stations and select other merchants. At WEX, we provide fleet managers and operators with fuel discounts and the flexibility to configure spend controls that restrict fleet members to using their cards at configured merchants for configured amounts and velocity.

Responsibilities:

• Design, develop, and maintain robust, scalable, and high-performance object-orientated code in our backend services.
• Develop public REST APIs using Java and internal gRPC APIs for inter-service and inter-system communication.
• Craft systems designs, lead design decisions, and drive alignment with other senior engineers.
• Write automated unit tests, integration tests, end-to-end tests, concurrency tests, and load/performance tests.
• Analyse existing systems to identify bottlenecks and tech debt and implement scalability and stability improvements.
• Implement automation for testing, monitoring, healing, and scaling applications and continuous integration and deployment to reduce time to market
• Collaborate with cross-functional teams, including product managers, designers, and other engineers, to define and implement new features.
• Conduct code reviews (comment, approve, seek revisions, merge), mentor junior and mid-level engineers, and actively promote engineering best practices.
• Dive deep and troubleshoot complex issues, devise fixes, author root cause analysis documents, and ensure lasting performance and reliability.
• Conduct objective and comparative analyses of competing technologies to advise the team of pros and cons of a technology solution
• Maintain 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 improvement.
• Drive cross-team projects as a single-threaded owner (STO) or tech lead and actively unblock other engineers to make progress.

Requirements:

• Bachelor's degree in Computer Science or Software Engineering
• 5-8 years of professional experience in software engineering.
• Strong understanding of data structures and algorithms, object-orientated design, and problem-solving skills.
• Expertise in designing and developing internet-scale services with scalability, availability, security, and reliability design tenets.
• Excellent written and verbal communication skills and a collaborative and empathetic mindset.
• Proficiency in backend development, with expertise in Java or C#, and frameworks like SpringBoot, building and optimizing RESTful APIs, ODATA framework, and SQL
• Ability to leverage AI-enabled development tools such as Cursor AI, Kiro and GitHub Copilot to accelerate feature delivery, automate documentation, and enhance code quality.

Preferred Qualifications:

• Master's degree in computer science or software engineering.
• 5 years of experience in software engineering.
• Experience with event-driven architecture and tools like Kafka.
• Experience working on card payments.
• Familiarity with cloud-native architecture (containerisation using tools such as Docker and Kubernetes).
• Awareness of API security and PCI DSS compliance requirements.
• Familiarity with mobile development (iOS or Android).
• Experience building AI skills and deploying AI solutions to production environments.
• Experience building production-grade AI agents or copilots.
• Familiarity with multi-agent systems and distributed AI architectures.
• Experience with vector databases (e. g., Pinecone, Weaviate, OpenSearch, and Milvus).
• Knowledge of AI evaluation techniques, safety practices, and responsible AI principles.