Senior Backend Engineer – AI Platform

🕒 September 21

🏄 California, Maine, +4 more states – Remote

🏄 California – Remote 🦞 Maine – Remote 🍂 Massachusetts – Remote 🤠 Texas – Remote ⛷️ Utah – Remote ☕ Washington – Remote

💵 $121.5k - $145.5k / year

⏰ Full Time

🟠 Senior

🔙 Backend Engineer

🦅 H1B Visa Sponsor

This company has sponsored H1B visas in the past.

👻 Ghost score 14%

What it means: how likely this posting is sitting open without active hiring.How to read it: 60% or higher means we think this is a ghost. Lower scores are less of a worry.How we score it: age, reposts, open roles vs team size, how fast jobs close, and whether pay is listed.Fine print: an estimate from public data, not a judgment of the company. Real jobs can score high, so treat it as a hint, not a fact.

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WEX

WebsiteLinkedInAll Job Openings

5001 - 10000 employees

Founded 1983

🏥 Healthcare

📦 Logistics

✈️ Travel

💰 $310M Post-IPO Debt on 2020-06

Healthcare • Logistics • Travel

WEX is a global commerce platform specializing in various business solutions to address operational challenges. They provide services in managing and mobilizing fleets with their fuel card systems, offering comprehensive fleet management and analytics. Additionally, they focus on business payments solutions that streamline processes across industries, enhancing efficiency and security. WEX is also involved in employee benefits administration, helping organizations effectively manage health and reimbursement accounts. Their diverse range of services caters to numerous sectors, emphasizing innovation, sustainability, and effective solutions for business growth.

📋 Description

• Design, develop, and maintain robust, scalable, high-performance object-oriented backend services • Develop public REST APIs using Java and internal gRPC APIs • Architect and realize next-generation Agentic AI Platform capabilities • Design and build agentic AI systems and services for autonomous workflows, reasoning, and task execution • Develop AI agents with orchestration, tool usage, memory, and multi-step decision-making • Implement and scale multi-agent architectures for payments and fleet ecosystems • Integrate AI agents, APIs, and enterprise data sources using MCP or similar frameworks • Build and optimize LLM-powered services for production performance, reliability, and cost efficiency • Implement evaluation frameworks, observability, and guardrails for AI systems • Design context management, memory, and retrieval-augmented generation solutions • Craft system designs, lead design decisions, and align with senior engineers • Write unit, integration, end-to-end, concurrency, and load/performance tests • Identify bottlenecks and technical debt and implement scalability and stability improvements • Automate testing, monitoring, healing, scaling, continuous integration, and deployment • Collaborate with product managers, designers, and engineers on new features • Conduct code reviews and mentor junior and mid-level engineers • Troubleshoot complex issues, author root cause analyses, and improve reliability • Analyze competing technologies and advise on technology solutions • Maintain design documents, runbooks, change-management documents, and readiness plans • Support production applications through monitoring and rapid incident resolution • Lead cross-team projects as a single-threaded owner or tech lead and unblock engineers

🎯 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-oriented design, and problem-solving • Expertise designing and developing internet-scale services with scalability, availability, security, and reliability principles • Proficiency in backend development with Java or C#, SpringBoot, 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 • Preferred: Master’s degree in computer science or software engineering • Preferred: 8+ years of software engineering experience • Preferred: Python, Java, event-driven architecture, and Kafka • Preferred: Experience working on card payments • Preferred: Docker and Kubernetes • Preferred: API security and PCI DSS compliance • Ability to work on existing codebase, contribute improvements, and adapt to legacy systems’ constraints • Nice to have: AI skills and production AI solutions • Nice to have: Production-grade AI agents or copilots • Nice to have: Multi-agent systems and distributed AI architectures • Nice to have: Vector databases such as Pinecone, Weaviate, OpenSearch, or Milvus • Nice to have: AI evaluation techniques, safety practices, and responsible AI principles

🏖️ Benefits

• Health insurance • Dental insurance • Vision insurance • Retirement savings plan • Paid time off • Health savings account • Flexible spending accounts • Life insurance • Disability insurance • Tuition reimbursement • Quarterly or annual bonus eligibility for non-sales roles