Principal Engineer

Overview

Connecting clients to markets – and talent to opportunity.

With 5,400+ employees and over 80,000 institutional, commercial, and payments clients, we operate from more than 80 offices spread across six continents. As a Fortune 100, Nasdaq-listed provider, we connect clients to the global markets – focusing on innovation, human connection, and providing world-class products and services to all types of investors.

Whether you want to forge a career connecting our retail clients to potential trading opportunities, or ingrain yourself in the world of institutional investing, StoneX Group is made up of four business segments that offer endless potential for progression and growth.

Business Segment Overview

Corporate: Engage in a deep variety of business-critical activities that keep our company running efficiently. From strategic marketing and financial management to human resources and operational oversight, you'll have the opportunity to optimize processes and implement game-changing policies.

Responsibilities

Position Purpose

We are seeking a Principal Engineer with deep agentic development experience to lead major components of our Payments technology transformation. You will architect, design, and implement mission‑critical distributed systems while driving adoption of agent‑powered engineering using tools such as Claude Code and emerging autonomous development agents.

This role sets technical direction, accelerates delivery using AI‑augmented workflows, and enables engineering teams to achieve 10-20 productivity improvements through structured, agent‑ready codebases.

Primary duties will include:

• Architecture & Technical Leadership
• Lead the design and development of distributed, microservice‑based enterprise applications using Java, Spring Boot, and cloud‑native patterns.
• Shape the future Payments platform architecture and contribute to front‑to‑back re‑engineering initiatives across GP.
• Drive system design excellence through formal design reviews, ADRs, and technical deep‑dives.
• Ensure high standards for reliability, performance, scalability, and observability.
• Agentic Development Leadership
  
  

This is the major differentiator of the role.

• Introduce, design, and operationalize agent‑based engineering workflows across the SDLC.
• Use tools such as Claude Code, capable of repository‑wide reasoning, automated refactoring, debugging, and commit generation to accelerate engineering throughput.
• Build agent‑ready codebases through modular design, clean documentation, and comprehensive test coverage — key enablers of successful agentic development.
• Actively contribute to and/or lead the new agentic development team for Payments (e.g., new wallet solution POC).
• Evaluate AI‑generated code for quality, correctness, architectural alignment, and security.
• Develop internal best practices, training materials, and standards for agent‑accelerated engineering.
• Delivery & Execution
• Deliver high‑quality software aligned to business needs and customer outcomes.
• Translate product requirements into scalable technical solutions; break down complex features into actionable tasks.
• Implement robust automated testing and continuous integration practices.
• Diagnose, debug, and resolve complex issues across distributed systems and environments.
• Coaching, Mentoring & Technical Culture
• Mentor senior and junior engineers on system design, coding best practices, and agent‑centric engineering patterns.
• Promote collaborative working across global agile teams.
• Champion engineering excellence, continuous improvement, and experimentation with AI‑accelerated development.
  
  

Qualifications

To land this role you will need:

Core Engineering Skills

(Aligned with existing Principal Engineer JDs)

• 12–15+ years in software engineering (back‑end or full‑stack).
• Expertise with Java, Spring Boot, microservices, cloud-native patterns, and distributed systems.
• Strong understanding of cloud platforms (Azure or AWS) and containerization (Docker/Kubernetes).
• Messaging technologies (Kafka, RabbitMQ, Azure Service Bus).
• Experience with SQL and NoSQL databases (SQL Server, MongoDB).
• Solid grasp of CI/CD, Git, DevOps tooling, test automation frameworks.
• Experience in cross‑border payments or financial markets.
• Leading or participating in large transformation programs.
• Prior experience introducing new engineering methodologies (AI/ML, agentic, DevOps, cloud migrations.
• Opportunity to build the future of global payments technology with a modern, cloud‑native and agent‑augmented engineering stack.
• Work alongside global engineering and product teams driving cutting‑edge innovation.
• Competitive compensation and benefits.
• A culture that values autonomy, ownership, continuous learning, and experimentation.
  
  

Agentic Development Skills

(What makes this role unique)

• Hands‑on experience with agentic development tools such as Claude Code, Copilot Workspace, or equivalent.
• Ability to orchestrate multi‑agent workflows (refactoring, debugging, dependency updates, code generation).
• Deep understanding of how design quality affects agent output (modularity, documentation, test coverage).
• Experience evaluating and validating AI‑generated code.
• Ability to build frameworks, patterns, and tooling for agent‑powered engineering at scale.
  
  

Soft Skills

• Strong analytical, problem‑solving, and communication skills.
• Ability to collaborate effectively across distributed global teams.
• Forward‑thinking mindset and deep curiosity about emerging technologies in payments and AI.
  
  

Education

• Degree in Computer Science, Engineering, or related field.