Senior AI Engineer - Agentic AI & LLM Platforms

Cantor Fitzgerald; New York (NY); On-site; USD 300,000 - 350,000; Full time

Job summary

FMX Services, LLC is seeking an experienced AI Engineer to join the Fenics UST Development department in New York. You will design and build AI-powered applications for our exchange business, focusing on agentic workflows, LLM-powered systems, and reliable architectural patterns.

You will mentor engineers, contribute to strategic AI initiatives, and ensure production-grade quality through testing, security, and responsible AI practices.

Qualifications

• Bachelor's degree in computer science or related technical field.
• 5+ years of professional software engineering experience, including production systems.
• 2+ years of hands-on experience developing AI or LLM-powered applications.
• Demonstrated experience building agentic AI systems with tool-using agents and multi-step workflows.
• Strong programming skills in C++ and Python with production-ready code.
• Experience with modern LLM development patterns, prompts, and structured outputs.
• Understanding of LLM failure modes and mitigation strategies.
• Experience designing evaluation frameworks for AI applications and test data sets.
• Hands-on experience with APIs, microservices, and cloud deployment.
• Strong understanding of security, privacy, and responsible AI considerations.

Responsibilities

• Design, build, and maintain production-grade AI applications for FMX's exchange business.
• Develop agentic AI workflows utilizing LLMs, tool use, planning, and structured outputs.
• Architect reliable AI application patterns with human-in-the-loop controls and monitoring.
• Evaluate LLM-powered systems using quantitative and qualitative methods, including benchmark design and red-team testing.
• Analyze model behavior, identify failure modes, and implement improvements for accuracy and reliability.
• Build and integrate APIs, data pipelines, and vector databases to support AI development.
• Apply software engineering best practices, including clean architecture and automated testing.
• Partner with cross-functional teams to translate business needs into technical designs.
• Contribute to technical strategy and architectural decisions for AI platforms and reusable components.
• Mentor other engineers and raise the team's AI engineering capabilities.

Skills

C++

Python

LLM development

Agentic AI

Production software

Education

Bachelor's degree in computer science or related field

Tools

APIs

Cloud deployment

Vector databases

Microservices

Job description

FMX Services, LLC is seeking an experienced AI Engineer to join the Fenics UST Development department in New York. You will design and build AI-powered applications for our exchange business, focusing on agentic workflows, LLM-powered systems, and reliable architectural patterns.

You will mentor engineers, contribute to strategic AI initiatives, and ensure production-grade quality through testing, security, and responsible AI practices.