Lead Fullstack Engineer (.NET & React) with Agentic Dev

Overview

Permanent, full-time, hybrid 

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: A Swift-accredited service bureau and member, our Payments division provides NGOs, institutions and non-profits the ability to make a local difference, globally – with transparent pricing across 180+ countries and 140+ currencies. 

Responsibilities

Position Purpose: We are seeking a Lead Fullstack Engineer to lead the FX Payments engineering team through the next stage of platform evolution.

This role combines: 

• Hands-on fullstack engineering (.NET, React, Azure)

• Direct people leadership of a scrum team (~5 engineers)

• Architectural ownership of a critical product domain

• Operationalization of agentic development practices within the team

You will be accountable for engineering quality, delivery predictability, and team capability growth — while driving the practical adoption of agent-powered workflows that measurably improve productivity and code quality.

This is a high-impact leadership role for a senior engineer ready to shape both systems and engineering culture.

Key Responsibilities will include:

1. Technical & Architectural Leadership 

• Own the technical direction of FX Payments within your domain.

• Lead design and evolution of scalable, maintainable fullstack solutions using:

  • C# / .NET (backend APIs and services)

  • React / TypeScript (modern frontend architecture)

  • Azure cloud-native services

• Ensure architectural decisions support performance, resiliency, observability, and regulatory compliance.

• Conduct structured design reviews and maintain architectural documentation and ADRs.

• Drive modernization of legacy components toward modular, testable, cloud-ready patterns.

2. Agentic Development Leadership

This is a defining aspect of the role.

• Introduce and standardize agent-based engineering workflows within the team (e.g., Claude Code, Copilot Workspace, or equivalent).

• Enable the team to safely leverage AI agents for:

  • Code refactoring

  • Test generation

  • Debugging assistance

  • Documentation improvement

  • Dependency upgrades

• Ensure all AI-generated code is reviewed rigorously for:

  • Architectural alignment

  • Security vulnerabilities

  • Regulatory compliance

  • Maintainability

• Improve the “agent-readiness” of the codebase through:

  • Modular design

  • Clear domain boundaries

  • Strong test coverage

  • High-quality documentation

• Establish team-level best practices for safe, auditable AI-assisted development.

• Partner with Principal Engineers and platform leaders to align with broader agentic engineering standards.

Your objective is not experimentation alone — but measurable improvements in throughput, quality, and developer effectiveness within your domain.

3. Delivery Ownership & Execution Excellence 

• Lead and manage a cross-functional scrum team (~5 engineers).

• Drive effective refinement — translating product requirements into clear, technically sound work items.

• Maintain predictable delivery through disciplined planning, risk management, and dependency tracking.

• Contribute production-ready code across backend and frontend components.

• Ensure strong CI/CD, automated testing, and deployment hygiene.

• Partner closely with Product, QA, and Architecture stakeholders.

4. People Leadership & Engineering Culture

• Provide direct people management, coaching, and performance feedback.

• Mentor engineers in:

  • System design

  • Clean coding standards

  • Cloud-native patterns

  • Responsible use of agentic tooling

• Build a culture of ownership, accountability, and continuous improvement.

• Encourage experimentation with guardrails — balancing innovation with production stability.

• Identify skill gaps and support targeted upskilling (including AI-augmented engineering practices).

Qualifications

To land this role you will need:

Core Fullstack Engineering 

• Significant experience as a senior or lead fullstack engineer.

• Strong backend expertise in C# / .NET (REST APIs, distributed systems).

• Deep hands-on experience with React and modern frontend architecture (TypeScript, component-driven design, state management).

• Azure cloud experience (App Services, Functions, Kubernetes, containerized workloads).

• Strong understanding of scalable system design, performance tuning, and distributed architecture.

• Experience with CI/CD pipelines, automated testing frameworks, and DevOps practices.

Agentic Development Capabilities

• Hands-on experience using AI-assisted development tools (e.g., Claude Code, GitHub Copilot, Copilot Workspace, or equivalent).

• Ability to guide a team in adopting AI tools responsibly within enterprise environments.

• Understanding of how modular architecture, documentation quality, and test coverage impact AI agent effectiveness.

• Experience reviewing and validating AI-generated code for correctness and maintainability.

• Strong judgment in balancing acceleration with governance and security.

Leadership & Collaboration

• Proven experience leading small engineering teams.

• Strong facilitation skills for refinement and technical discussions.

• Ability to communicate architectural decisions and delivery risks clearly.

• Experience working in Agile, cross-functional environments.

• Strong stakeholder management and collaboration skills.

Education / Certification Requirements: 

• Bachelor’s degree in information technology.

Working environment: 

• Hybrid 4-days in office.