[Remote] Senior Backend Engineer – AI Platform

Note: The job is a remote job and is open to candidates in USA. WEX Inc. is a company focused on mobility solutions, and they are seeking a Senior Backend Engineer to join their Platform team. This role involves designing and developing AI platforms to support feature development, enabling robust and scalable solutions for autonomous AI agents and complex workflows in the fintech space.

Responsibilities

• Design, develop, and maintain robust, scalable, and high-performance object oriented 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, load/performance tests
• Analyze existing systems to identify bottlenecks, tech debt, and implement scalability, and stability improvements
• Implement automation for testing, monitoring, healing, and scaling applications, 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
• Design and build agentic AI systems and services, enabling autonomous workflows, reasoning, and task execution within Mobility platforms
• Develop AI agents from scratch, including orchestration, tool usage, memory, and multi-step decision-making capabilities
• Implement and scale multi-agent architectures to support complex, distributed use cases across payments and fleet ecosystems
• Integrate systems using Model Context Protocol (MCP) or similar frameworks to enable secure and scalable interaction between AI agents, APIs, and enterprise data sources
• Build and optimize LLM-powered services (e.g., OpenAI APIs, LangChain) for production-grade performance, reliability, and cost efficiency
• Implement evaluation frameworks, observability, and guardrails to ensure correctness, safety, and compliance of AI-driven systems
• Design solutions for context management, memory, and retrieval-augmented generation (RAG) to enhance agent effectiveness

Skills

• 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-oriented 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#, frameworks like SpringBoot, building and optimizing RESTful APIs, ODATA framework, and SQL
• Hands-on experience building or contributing to AI/LLM-powered applications or agent-based systems
• Familiarity with agent frameworks, tool-use patterns, and orchestration of LLM workflows
• Experience integrating AI systems with external tools/APIs using MCP or similar protocols
• Understanding of prompt engineering, embeddings, and vector-based retrieval systems
• Experience designing systems for scaling AI workloads in production environments
• Master's degree in computer science or software engineering
• 8+ years of experience in software engineering
• Experience with Python, Java, event-driven architecture and tools like Kafka
• Experience working on card payments
• Familiarity with cloud-native architecture (containerization using tools such as Docker and Kubernetes)
• Awareness of API security and PCI DSS compliance requirements
• Ability to work on existing codebase, contribute improvements, and adapt to legacy systems' constraints
• Experience building AI skills & 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, Milvus)
• Knowledge of AI evaluation techniques, safety practices, and responsible AI principles

Benefits

• Commission under the terms of an applicable plan for most sales positions
• Quarterly or annual bonus based on their role and applicable plan for non-sales roles
• Health, dental and vision insurances
• Retirement savings plan
• Paid time off
• Health savings account
• Flexible spending accounts
• Life insurance
• Disability insurance
• Tuition reimbursement

Company Overview

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