Principal Software Engineer / Architect – AI – Legal FDE

Summary: The Principal Software Engineer / Architect leads the technical vision and strategy for AI solutions within the Forward Deployed Engineering team. This hands-on role involves designing complex, high-risk AI systems, mentoring staff engineers, and partnering with product and business leadership to align techn...

Job Description

Thomson Reuters is looking for a recognized technical authority to set the direction for how the world's top law firms and corporate legal departments adopt AI. CoCounsel is trusted by over 20,000 law firms and corporate legal departments, including the majority of top US courts and Am Law 100 firms, and is used by one million professionals across 107 countries.

As the senior-most individual contributor on the Forward Deployed Engineering (FDE) team, you will define and drive the technology strategy and roadmap for designing, building, and operating bespoke AI solutions. You will own the team's most complex, highest-risk, and most strategically important engagements, working alongside Staff Software Engineers and Architects, Senior Legal AI Engineers, and AI Solution Engineers. You will partner with Product, Engineering, and business leadership to align FDE work with CoCounsel's long-term objectives.

This is a hands-on technical leadership role with broad influence. You will make high-stakes architectural decisions with autonomy, raise the engineering bar across the team and beyond, and help make the team AI-native in everything it does.

Key Responsibilities

Technical Vision and Strategy

• Define and drive the long-term technical vision and strategy for FDE, including vision documents, technology requirements, and roadmaps tied to product and business objectives.
• Lead the selection, evaluation, and adoption of technologies, frameworks, and patterns, and build consensus across teams.
• Identify where emerging capabilities such as agentic systems, MCP and A2A interoperability, and new model and orchestration patterns could cause a transformational shift, and communicate the opportunities and trade-offs to senior leadership.
• Contribute to cross-functional and cross-business-unit engineering strategy, standards, and, where appropriate, patents.

Architecture and Delivery of Complex AI Systems

• Lead complex, high-risk, high-visibility AI initiatives from concept through production, staying hands-on in design, prototyping, and code for the hardest problems.
• Architect scalable, secure AI systems that integrate with client environments, including document management systems, enterprise platforms, and legal technology ecosystems.
• Design RAG pipelines, multi-agent orchestration, event-driven backends, and agentic workflows using CoCounsel, Westlaw, and Practical Law capabilities, plus third-party AI APIs.
• Build reusable AI components, frameworks, and solution templates that scale delivery across the team.
• Set standards for MLOps/LLMOps, Infrastructure as Code, and CI/CD so delivery is secure, repeatable, and fast.
• Identify weaknesses in existing designs and drive remedies.

Quality, Observability, and Trust

• Set the strategy for AI monitoring and observability, covering performance, output quality, latency, cost, and production reliability risk.
• Own LLM evaluation, including accuracy, hallucination risk, citation quality, A/B testing, and red-teaming, and define quality benchmarks grounded in real legal workflows.
• Ensure every solution meets ethical AI, data protection, and enterprise security requirements.
• Drive operational excellence across the software development lifecycle, including post-launch measurement.

Client and Stakeholder Engagement

• Act as the senior technical voice in discovery on high-value engagements, scoping use cases, shaping architectures, and building credibility with legal and technical executives.
• Present complex technical concepts and strategy to audiences from engineers to business unit executives, and negotiate solutions between key stakeholders.
• Work with legal SMEs to translate professional reasoning and domain heuristics into pipeline design, evaluation criteria, and benchmarks.
• Anticipate customer and market needs and feed field insights back into the product roadmap.

Leadership, Mentorship, and Culture

• Mentor and coach Staff, Senior, and Lead engineers, and indirectly lead a small team of engineers and technical experts on ambiguous problems.
• Review architecture and design at team and sub-unit levels and give authoritative feedback.
• Strengthen engineering culture through knowledge sharing and by championing AI-native tools and practices.
• Work with program and project managers to bring the technical dimension into status and risk reporting, and consult on budgets for large programs where applicable.
• Represent Thomson Reuters externally through speaking, publications, community engagement, or open-source and standards participation.

Required Qualifications

• 12+ years of software engineering experience, with deep expertise in system design, distributed systems, and architecture, and a track record of leading highly complex, high-risk projects.
• Extensive experience owning technical requirements and strategy, setting technology roadmaps, and prioritizing between competing features and investments.
• Expert-level, hands-on experience building and deploying AI/ML and LLM-powered applications in production.
• Deep proficiency with orchestration frameworks such as LangChain, LangGraph, PydanticAI, or AutoGen, and expert understanding of RAG architectures and vector databases.
• Hands-on experience with Model Context Protocol (MCP) and Agent-to-Agent (A2A) patterns for interoperable, tool-augmented AI systems.
• Expert Python (FastAPI or equivalent), with strong experience in RESTful, async, and event-driven architectures.
• Experience with a major cloud platform (AWS, Azure, or GCP) and Infrastructure as Code (Terraform, CDK, or equivalent).
• Production observability experience (Datadog, Grafana, Prometheus, or similar) and experience with AI evaluation platforms (LangSmith, Langfuse, Braintrust, or W&B).
• Strong background in secure API development using OAuth 2.0, OpenID Connect, and JWT.
• Demonstrated fluency with AI-assisted development tools (Claude Code, Cursor, GitHub Copilot) and a track record of driving AI-native engineering practices.
• Proven ability to influence across teams and domains, advise senior leadership, and communicate complex ideas at multiple levels of an organization.
• Autonomy, sound judgment, comfort with ambiguity in a fast-paced agile environment, and strong attention to detail.
• Recognized as a technical role model and leader in your field.

Preferred Qualifications

• Experience in a regulated industry (legal, fintech, or healthcare), with familiarity with compliance and data privacy requirements.
• Experience building agentic AI systems with autonomous decision-making.
• Familiarity with legal platforms, document management systems, and legal technology ecosystems.
• Container orchestration (Docker/Kubernetes) and MLOps/LLMOps lifecycle management.
• Understanding of transformer model scaling, limitations, and fine-tuning.
• External presence through conference talks, publications, patents, open-source contributions, or standards participation.
• Experience developing vision documents and leading cross-business-unit technology strategy.

#LI-GK1

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 (Y)our 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.
• Making a Real-World Impact: 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, Thomson Reuters 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, Thomson Reuters 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. Finally, Thomson Reuters offers the following 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.

Thomson Reuters complies with local laws that require upfront disclosure of the expected pay range for a position. 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.
For any eligible US locations, unless otherwise noted, the base compensation range for this role is $158,900 USD - $295,100 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

Thomson Reuters 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 Thomson Reuters, 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. Sound exciting? Join us and help shape the industries that move society forward.

As a global business, we rely on the unique backgrounds, perspectives, and experiences of all employees to deliver on our business goals. 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. Thomson Reuters is proud to be an Equal Employment Opportunity Employer providing a drug-free workplace.

Thomson Reuters makes reasonable accommodations for applicants with disabilities, including veterans with disabilities, and for sincerely held religious beliefs in accordance with applicable law. If you reside in the United States and require an accommodation in the recruiting process, you may contact our Human Resources Department at HR.Leave-Expert@thomsonreuters.com. 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. Please note this email is not intended for general recruitment questions and we will promptly respond to inquiries regarding accommodations. More information on requesting an accommodation [here.](https://www.thomsonreuters.com/en/careers/our-commitment-to-candidates)

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