Principal Software Engineer - .NET, AWS & AI

About the Role

Are you excited by the opportunity to shape the future of high-performance, scalable, reliable, and resilient enterprise software? Thomson Reuters is seeking a hands‑on Principal Software Engineer with deep, recent C#/.NET Core and AWS experience building large-scale distributed systems and cloud‑native platforms, along with experience applying AI/ML, Generative AI, large language models (LLMs), retrieval‑augmented generation (RAG), or agentic AI capabilities in production environments.

This is a Principal‑level individual contributor role requiring demonstrated ownership of architecture and technical direction for complex, enterprise‑scale production systems. The successful candidate will have operated at Principal Engineer or equivalent scope, influencing multiple engineering teams while remaining actively hands‑on with architecture, design, development, and implementation.

You will play a key role in the modernization and evolution of our U.S. tax compliance solutions, helping establish technical direction, improve platform scalability and reliability, and responsibly incorporate AI‑enabled capabilities into our products. Candidates outside the Washington, DC area must be willing and able to travel to the Washington, DC office as needed.

Own architecture and system design for complex, large‑scale production platforms, making technical decisions around scalability, reliability, performance, security, and maintainability.

Design and build production software using C#/.NET Core and AWS, remaining actively involved in implementation, technical problem‑solving, design reviews, and engineering delivery.

Lead the modernization of complex legacy applications into cloud‑native architectures, including distributed systems, microservices, APIs, data services, and containerized workloads.

Establish technical direction and influence architecture and engineering decisions across multiple teams.

Provide hands‑on technical leadership through architecture and design reviews, code guidance, troubleshooting, mentoring, and engineering best practices.

Identify and help implement opportunities to incorporate AI/ML and Generative AI capabilities into production products.

Contribute to the long‑term technical roadmap and communicate architecture decisions, trade‑offs, risks, and recommendations.

About You

You're a fit for this Principal Software Engineer role if you bring:

• 10+ years of professional software engineering experience with demonstrated Principal Engineer or equivalent senior individual contributor scope.
• Strong, recent, hands‑on C#/.NET Core engineering experience, including personally designing and implementing production software.
• Deep, hands‑on production experience with Amazon Web Services (AWS), designing and implementing cloud‑native systems using multiple AWS services such as EC2, S3, Elastic Load Balancing, Auto Scaling, RDS, Lambda, SQS, and container services.
• Proven experience architecting and implementing large‑scale distributed systems, microservices, APIs, and highly available production applications.
• Demonstrated experience modernizing complex legacy applications into scalable, resilient cloud‑native solutions.
• Principal‑level architecture and system design ownership, including making significant technical trade‑offs, setting technical direction, and influencing engineering decisions across multiple teams.
• Proven ability to remain hands‑on with engineering delivery while providing Principal‑level technical leadership.
• Strong knowledge of software architecture, object‑oriented design, data structures, algorithms, design patterns, API design, relational databases, and modern engineering practices.
• Strong communication and collaboration skills with the ability to influence across Product, Engineering, Security, Quality Assurance, Data, and Operations.
• Bachelor's degree in Computer Science or a related technical discipline, or equivalent practical experience.
• Experience designing, building, or integrating production AI/ML, Generative AI, LLM, RAG, or agentic AI capabilities is highly preferred.
• Experience with containers, Kubernetes, API gateways, infrastructure automation, Python, TypeScript, Node.js, React, or Angular is preferred.

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 wellbeing.
• Culture: Globally recognized, award‑winning reputation for inclusion and belonging, flexibility, work‑life balance, and more. We live by our values: Obsess over our Customers, Compete to Win, Challenge Your Thinking, Act Fast / Learn Fast, and Stronger Together.
• Social Impact: Make an impact in your community with our Social Impact Institute. We offer employees two paid volunteer days off annually and opportunities to get involved with pro‑bono consulting projects and Environmental, Social, and Governance (ESG) initiatives.
• We are one of the few companies globally that helps its customers pursue justice, truth, and transparency. Together, with the professionals and institutions we serve, we help uphold the rule of law, turn the wheels of commerce, catch bad actors, report the facts, and provide trusted, unbiased information to people all over the world.
• In the United States, ThomsonReuters offers a comprehensive benefits package to our employees. Our benefit package includes market competitive health, dental, vision, disability, and life insurance programs, as well as a competitive 401k plan with company match. In addition, ThomsonReuters offers market leading work life benefits with competitive vacation, sick and safe paid time off, paid holidays (including two company mental health days off), parental leave, sabbatical leave. These benefits meet or exceeds the requirements of paid time off in accordance with any applicable state or municipal laws.
• Additional benefits: optional hospital, accident and sickness insurance paid 100% by the employee; optional life and AD&D insurance paid 100% by the employee; Flexible Spending and Health Savings Accounts; fitness reimbursement; access to Employee Assistance Program; Group Legal Identity Theft Protection benefit paid 100% by employee; access to 529 Plan; commuter benefits; Adoption & Surrogacy Assistance; Tuition Reimbursement; and access to Employee Stock Purchase Plan.
• The base compensation range varies across locations. Eligible office location(s) for this role include one or more of the following: New York City, San Francisco, Los Angeles, and/or Irvine, CA; McLean, VA; Washington, DC. The base compensation range for the role in any of those locations is $183,100 USD - $340,000 USD. Base pay is positioned within the range based on several factors including an individual’s knowledge, skills and experience with consideration given to internal equity. Base pay is one part of a comprehensive Total Reward program which also includes flexible and supportive benefits and other wellbeing programs. This role may also be eligible for an Annual Bonus based on a combination of enterprise and individual performance.

About Us

ThomsonReuters informs the way forward by bringing together the trusted content and technology that people and organizations need to make the right decisions. We serve professionals across legal, tax, accounting, compliance, government, and media. Our products combine highly specialized software and insights to empower professionals with the data, intelligence and solutions needed to make informed decisions, and to help institutions in their pursuit of justice, truth, and transparency. Reuters, part of ThomsonReuters, is a world leading provider of trusted journalism and news. We are powered by the talents of 26,000 employees across more than 70 countries, where everyone has a chance to contribute and grow professionally in flexible work environments. At a time when objectivity, accuracy, fairness, and transparency are under attack, we consider it our duty to pursue them.

Our Employer Story. Inside ThomsonReuters Blog Awards and Recognition Join Our Talent Community Protect Your Job Search Future‑ready careers Our focus on a skills‑first approach ensures you’ll have the tools and knowledge to grow, lead, and thrive in an AI‑enabled future.

Equal Opportunity / Diversity / Inclusion

To ensure we can do that, we seek talented, qualified employees in all our operations around the world regardless of race, color, sex/gender, including pregnancy, gender identity and expression, national origin, religion, sexual orientation, disability, age, marital status, citizen status, veteran status, or any other protected classification under applicable law.

ThomsonReutersisproudtobeanEqualEmploymentOpportunityEmployerprovidingadrug‑freeworkplace.

ThomsonReutersmakesreasonableaccommodationsforapplicantswithdisabilities,includingveteranswithdisabilities,andforsincerelyheldreligiousbeliefsinaccordancewithapplicablelaw.

If you reside in the United States and require an accommodation in the recruiting process, you may contact our Human Resources Department at View email address on click.appcast.io.

Disability accommodations in the recruiting process may include things like a sign language interpreter, making interview rooms accessible, providing assistive technology, or other relevant accommodations.

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More information on requesting an accommodation here. Learn more about a career with us. More information about Thomson Reuters can be found on thomsonreuters.com At Thomson Reuters, we’re not riding the AI wave - we’re reshaping the future of professional work across law, tax, compliance, and journalism. Here, you will collaborate with smart, ambitious people who thrive on solving complex problems, delivering market‑leading solutions, and innovating with curiosity and care.