Principal Software Engineer – .NET, AWS & AI

Principal Engineer

Are you inspired by the opportunity to shape the future of AI-driven technology and lead the development of the next generation of high-performance, scalable, reliable, and resilient tax and accounting software ecosystems? At Thomson Reuters, we invite you to join our Tax and Accounting team as we set the technical direction for our US tax compliance solutions. In this role, you will play a key part in delivering innovative, user-focused products that transform the tax compliance landscape and drive meaningful impact for our clients.

About the role:

We are seeking a hands-on Principal Engineer with strong, recent experience in C#/.NET Core and AWS. The ideal candidate has designed and delivered large-scale, production systems and has demonstrated Principal-level ownership of architecture, distributed services, APIs, cloud-native applications, and technical direction. This individual will work cross-functionally across Product, Engineering, Security, QA, Data, and Operations while remaining actively involved in implementation and delivery

Technical Leadership: Serve as a technical leader within the organization, providing guidance, mentoring, and direction to software engineers at all levels. You provide strategic direction, set engineering and technical standards, and drive innovation across multiple projects or domains.

AI vision and Strategy : Collaborate to identify opportunities for new AI-powered product features, enhancements, and product expansions to differentiate our products from competitors. Identify opportunities for innovation, assess emerging technologies and proactively apply them in our product.

Continuous Learning and Development : Foster a culture of continuous learning and development within the engineering team. You encourage skill-building initiatives and lead by example by staying abreast of industry trends, emerging technologies, and best practices.

Technical Governance: Establish and enforce technical governance standards, including coding standards, design patterns, and development methodologies. You ensure consistency, quality, and scalability across projects and teams

Technical Roadmap and Architectural Design : Contribute to the development of the technical roadmap, outlining the future direction of the product line’s technology stack, infrastructure, and development processes. Assess technology risks, evaluate trade-offs, and make informed decisions that align with the company's long-term goals. Communicate technical concepts and decisions clearly to both technical and non-technical stakeholders. Lead design reviews to ensure proposed solutions meet scalability, performance, and maintainability requirements

Problem Solving and Troubleshooting : When complex technical issues arise, principal engineers provide leadership in troubleshooting and resolving them. You leverage your expertise to diagnose problems, propose solutions, and guide the team towards resolution. Effective communication and documentation are essential aspects of the role.

Thought Leadership : Represent the company as technical expert in industry forums, conferences, and events. You provide thought leadership and guide the business to evolve our products in the modern AI landscape and share insights on emerging trends and best practices.

About you:

You´re a good fit for the role of Principal Engineer if your background includes:

Candidates who are not located in the Washington, DC area must be willing and able to travel to the Washington, DC office as needed.

10+ years of hands-on software engineering experience with a proven record of developing scalable and resilient web-based products and solutions. Bachelor’s or Master’s degree in Computer Science or related field.

Strong Computer Science fundamentals in Data Structures and algorithm design. Strong programming experience with .Net stack. You will need to have strong object-oriented design and development skills. You possess a solid understanding of object-oriented programming, SOLID, DRY, DDD and core database design principles.

Proven track record in applying architecture and design patterns to solve complex business problems

Demonstrated experience in designing and developing customer facing high traffic and performant REST APIs using ASP.Net or similar frameworks; experience with API gateways is a plus.

Expertise with modern UI frameworks (React, Angular, or similar), TypeScript, Node.js, and Python.

Experience with AI technologies, including GenAI concepts such as prompt engineering, retrieval-augmented generation (RAG), and fine-tuning.

Experience working with public cloud infrastructure preferably AWS (EC2, S3, ALB, Auto Scaling, RDS, Lambda function, SQS, Containers).

Excellent interpersonal and communication skills, with the ability to influence across organizational boundaries and to navigate ambiguity, make data-driven decisions, and deliver results in a fast-paced environment.

Demonstrated ability to mentor others and promote best practices in devops practices, AI dev tools, and test-driven development.

Willingness to learn and support our legacy codebase while the transition to our next- generation is occurring. Proven track record of modernizing highly complex legacy web application to cloud native solution.

Demonstrated experience building and launching new products, platforms, services, APIs, or major capabilities from concept or prototype through production. The ideal candidate has personally defined architecture, service boundaries, technical standards, and delivery practices while remaining hands-on throughout development, deployment, scaling, and ongoing support.

Demonstrated experience building and launching new products, platforms, services, APIs, or major capabilities from concept or prototype through production. The ideal candidate has personally defined architecture, service boundaries, technical standards, and delivery practices while remaining hands-on throughout development, deployment, scaling, and ongoing support.

KEY:

Strong, recent hands-on engineering experience with C#/.NET Core and AWS .

Principal-level ownership of architecture and system design for large-scale production systems .

Experience building enterprise distributed systems, microservices, APIs, and cloud-native applications.

Experience building or integrating production AI/ML, Generative AI, LLM, RAG, or intelligent automation capabilities into customer-facing products.

Proven ability to work across Product, Engineering, Security, QA, Data, and Operations.

Ability to set technical direction, influence multiple teams, and remain hands-on with engineering delivery.

#LI-TH1

What’s in it For You?

• •Hybrid Work Model: We’ve adopted a flexible hybrid working environment for our office-based roles while delivering a seamless experience that is digitally and physically connected.
• •Flexibility & Work-Life Balance: Flex My Way is a set of supportive workplace policies designed to help manage personal and professional responsibilities, whether caring for family, giving back to the community, or finding time to refresh and reset. This builds upon our flexible work arrangements, including work from anywhere for up to 8 weeks per year, empowering employees to achieve a better work-life balance.
• •Career Development and Growth: By fostering a culture of continuous learning and skill development, we prepare our talent to tackle tomorrow’s challenges and deliver real-world solutions. Our Grow My Way programming and skills-first approach ensures you have the tools and knowledge to grow, lead, and thrive in an AI-enabled future.
• •Industry Competitive Benefits: We offer comprehensive benefit plans to include flexible vacation, two company-wide Mental Health Days off, access to the Headspace app, retirement savings, tuition reimbursement, employee incentive programs, and resources for mental, physical, and financial